Why I Finally Understand Why I Watched a Boring Movie to the End: The ''Sunk Cost Trap'' That Ruins Us

“Are You Stuck Thinking About Getting Your Money’s Worth?” – The Strange Accounting Book Inside Us

An hour into watching a movie you paid 15,000 won for. The story is painfully dull, and the actors’ performances are awkward. Your friend next to you whispers, “Should we just leave?” But somewhere in your mind, a voice shouts, “No! My 15,000 won! I have to get my money’s worth somehow!” So you stay, nodding off, until the credits roll.

Or think about when you splurged on an expensive pasta at a fancy restaurant, but it tastes worse than expected. Even though you’re full, you force yourself to finish the plate thinking, “This cost so much.” Eventually, you end up with indigestion.

Our daily lives are full of strange decisions where we give up current pleasure and future benefits because of money or effort already spent. We often call this “getting your money’s worth.” Behavioral economics names this phenomenon the “sunk cost fallacy.” “Sunk costs” literally mean costs buried in the ground that can never be recovered—like spilled water, past time, or spent money. According to economics textbooks, rational humans should not consider sunk costs in future decisions. They should ignore past costs and choose what benefits them most at the moment. So why do we fail to follow this simple rule and get trapped by past costs?

Everyday Traps: Our Lives Are Full of Sunk Costs

The sunk cost trap isn’t limited to movie tickets or food bills. Our lives are surrounded by traps of sunk costs big and small. Have you ever experienced these?

• Falling stocks and the temptation to “average down”: Stocks you invested in with high hopes keep falling. Rationally, you should cut losses and invest elsewhere, but many investors add more money to lower their average purchase price. The thought is, “If I sell now, I lock in losses, but if I average down and break even, I can get out.” This is a classic sunk cost fallacy. Warren Buffett advises, “If you realize you’re in a hole, the first thing to do is stop digging,” but we dig deeper to avoid the pain of loss.
• Ended relationships and “it’s a waste of the time we spent together”: Even when a relationship is unhappy and the future bleak, people hesitate to break up, saying, “We can’t break up because we’ve been together for five years.” They endure current unhappiness and give up future happiness due to the huge sunk cost of time and emotions. This applies not only to romantic relationships but also to long-term friendships or colleagues that no longer have a positive impact.
• Majoring in the wrong field and “wasting tuition”: When you realize your expensive college major doesn’t suit you, it’s hard to quit. You might tragically spend your life in a field that doesn’t fit because you don’t want to waste the time and money already invested. This becomes a huge sunk cost prison that traps personal potential.
• Side projects losing passion: Recently, an IT community shared stories of failed side projects, resonating with many. A promising project dragged on, team members lost enthusiasm, and reality set in. Objectively, stopping would benefit everyone, but no one dared to suggest quitting because of the time and effort already spent. After the project fizzled out, a designer lamented, “We struggled so much for two months, but it feels like nothing’s left.” This perfectly illustrates the deep loss left by sunk costs.

All these cases share one thing: the sunk cost fallacy isn’t just about money. It’s a flawed accounting of all finite resources we value—time, effort, emotions. Nobel laureate Richard Thaler’s concept of mental accounting clarifies this. Just as we manage money in separate budgets like “vacation fund” or “food expenses,” we mentally divide resources into invisible accounts like “time spent on Project A,” “emotions invested in B,” or “youth devoted to major C.” Deciding to give up means painfully closing that account with a “loss,” regardless of whether the currency is money, time, or feelings. Breaking up with a five-year partner hurts more than selling a 5 million won stock because the emotional sunk cost is heavier.

Why Can’t We Quit Because It’s “Wasteful”? – The Psychology of Sunk Costs

Our irrational trap is deeply linked to how our brain works. Behavioral economists identify three powerful psychological drivers behind the sunk cost fallacy: loss aversion, cognitive dissonance, and escalation of commitment.

The Root of All Evil: The Pain of Losing (Loss Aversion)

Our brain is wired to feel the pain of loss much more intensely than the pleasure of gain. Nobel laureates Daniel Kahneman and Amos Tversky’s Prospect Theory states people feel about twice as much psychological pain losing 1 million won as pleasure gaining the same amount.

This loss aversion is the core driver of the sunk cost fallacy. Leaving a boring movie midway confirms the loss of the ticket price now. Selling a stock turns a paper loss into a real, painful loss. To avoid this sharp pain, we gamble more time and money on uncertain hopes of breaking even later. It’s the mindset of “I’d rather endure a small pain now than face a possibly bigger pain later.”

Defending Pride: “I Wasn’t Wrong!” (Cognitive Dissonance and Self-Justification)

We all want to believe we are rational and wise decision-makers. When a past decision clearly turns out wrong, a severe psychological conflict arises between “I am wise” and “I made a foolish choice”—this is cognitive dissonance.

To ease this discomfort, we choose one of two paths: admit the mistake and reverse the decision, or deceive ourselves that the past decision was right and distort reality. Unfortunately, pride often pushes us toward the latter.

For example, imagine a department head who ambitiously introduced new software that employees complain about and that lowers efficiency. Stopping the project means publicly admitting a wrong judgment, hurting pride. So he justifies the decision by saying, “Employees just need more time to adapt,” and pours more resources into training. The desire to prove “My decision wasn’t wrong” traps him deeper.

Growing Obsession Like a Snowball: Escalation of Commitment

“I’ve come this far; I can’t quit now.”

The more time, money, and effort we invest, the stronger our emotional attachment and sense of responsibility become, making it hard to quit. Psychologist Barry Staw called this the escalation of commitment. What started as a small decision becomes emotionally charged: “I’ve put so much into this.”

This creates a dangerous feedback loop: initial investment → unexpected problems → “Since we’ve invested so much, let’s put in a little more” → more resources invested (deeper commitment) → bigger problems → “If we quit now, all efforts are wasted” → even more resources invested… This snowballs until the entire project collapses.

These three psychological forces don’t act independently; they fuel and reinforce each other, forming a psychological iron triangle that traps us. When a project falters, loss aversion ignites the emotional fire of “I don’t want to admit this loss.” Then cognitive dissonance pours fuel with self-justifications like “My first decision was right; just a bit more effort will fix it.” In this blaze, escalation of commitment logic pushes us deeper: “Since we’ve come this far, we must continue.” This powerful chain reaction makes the sunk cost fallacy a huge trap that’s hard to escape by willpower alone.

From the Concorde Fallacy to the Metaverse Mirage – The Museum of Failures

The sunk cost fallacy goes beyond personal mistakes, causing huge tragedies that change companies’ fates and shake national finances. History’s failures hold lessons we must remember.

Exhibit A: Timeless Classic Failures

• The Concorde Fallacy: The quintessential example of the sunk cost fallacy. In the 1960s, the UK and France started developing the supersonic passenger jet Concorde, promising a 3-hour Paris-New York flight. From the start, warnings about terrible fuel efficiency, noise, and high fares made the project unviable. Rationally, it should have been stopped immediately, but governments pushed on, reasoning, “We’ve already sunk astronomical R&D costs; we can’t quit now.” Ultimately, after spending $19 billion (about 25 trillion won in today’s value) and accumulating losses, operations ceased in 2003. The Concorde Fallacy remains a historic lesson on how national pride combined with sunk costs can cause disastrous outcomes.

• The Fall of Nokia and Kodak’s Tragedy: Nokia, once the king of mobile phones in the 2000s, failed to respond properly to the smartphone revolution led by iPhone and Android. They clung to their own OS, Symbian, due to the sunk costs in technology and investment, ignoring the market shift and losing their throne. Kodak’s tragedy is ironic: they invented the first digital camera but hesitated to switch due to sunk costs in their profitable film business. Fear that digital cameras would destroy their film sales held them back, turning Kodak into a relic of the past.

Exhibit B: New Disasters of Our Time

The sunk cost fallacy is not just history. Right now, new failures fueled by cutting-edge technology and massive capital are repeating around us.

• South Korea’s “Ghost Light Rail” Crisis: In the 2010s, many local governments jumped into light rail projects promising rosy futures. The results were disastrous. Yongin Light Rail predicted 161,000 daily riders but had only 9,000 at launch. Busan-Gimhae light rail’s actual demand was 17% of estimates, and Uijeongbu light rail faced bankruptcy with over 360 billion won in losses. The common factor? Demand forecasts were inflated, and warnings ignored. Once billions of won in taxes were spent and construction started, no one dared say “stop.” Political logic of “money already spent” overwhelmed economic rationality. Yongin city ended up with 850 billion won in debt and hundreds of billions in annual operating deficits covered by taxes—a “money-eating hippo.”
• The Metaverse Mirage: The metaverse craze from 2021 to 2023 is a perfect example of collective sunk cost fallacy. Facebook renamed Meta and invested tens of trillions of won in VR/AR losses. In Korea, conglomerates like KT and SKT and public institutions like Seoul city rushed to build metaverse platforms. But most platforms were empty, and services like KT’s Mincl and Seoul’s Metaverse Seoul quietly shut down amid user neglect. This was not just poor judgment but an industry-wide “blind investment” triggered by FOMO (Fear Of Missing Out). Once huge money and manpower poured in, the clear reality of “no users” was ignored in hope of eventual success, showing classic escalation of commitment.
• NFT Frenzy and the Rug Pull Tragedy: The NFT market, emerging alongside the metaverse, starkly reveals the psychology of sunk costs. Many NFT projects skyrocketed then became worthless overnight. An analysis shows 95% of NFT projects lost all value. Yet many investors can’t admit losses. Even when an NFT bought for 5 million won drops to 50,000 won, they won’t sell because selling locks in a 99% loss. They cling to worthless digital assets hoping “it will rise again someday.” This is a modern digital tragedy created by loss aversion.

These new failures teach us an important fact: the sunk cost fallacy can spread like a “collective epidemic” when combined with social trends or industry crazes. In the metaverse and NFT booms, one company’s investment pressured others not to fall behind, creating massive social sunk costs. In such an environment, it’s even harder for individuals to make rational decisions. When everyone runs in the same direction, it’s nearly impossible to stop alone and say, “This isn’t the right path.”

How to Escape the Hole – The Art of Cutting Losses and the Wisdom of Pivoting

We’ve seen how powerful and dangerous the sunk cost trap is. Is there a way out? Fortunately, understanding our irrationality leads to concrete strategies to overcome it. This is not just about stopping failure but turning failure into a stepping stone for success.

Your Rescue Toolbox

When you feel trapped by the sunk cost fallacy, try these tools. They help clear emotional fog and make rational decisions.

1. Ask the “Zero-Base” Question: The most powerful and immediate tool. Ask yourself, “If I forget all the money, time, and effort I’ve invested so far, and only consider what I know now, would I choose this path from the start?” This breaks past chains and forces the wisest choice now.
2. Set “Kill Criteria” in Advance: Before investing or starting a project, set clear “stop rules” without emotion. For example, “Sell this stock if it drops 20%,” or “Reevaluate if the project doesn’t meet goal X in 6 months.” Like a hiker who descends when weather turns bad, this helps act by preset rules, not feelings.
3. Practice a “Pre-Mortem”: Before starting, ask your team, “Imagine this project fails miserably in a year. What caused it?” This identifies risks early and helps set plans and kill criteria to avoid failure.
4. Borrow an Outsider’s Eye: The more involved we are, the less objective we become. Trusted friends, mentors, or experts can offer cold, clear perspectives. Ask, “Am I missing something?” Their view may reveal truths you can’t see.
5. Calculate Opportunity Cost: Shift focus from “what I lost” to “what I can gain.” For example, “Instead of watching this boring movie for another hour, I could read a good book or take a walk and be happier.” Analyzing opportunity cost gives courage to quit.
6. Use a Decision Matrix: To exclude emotions, list options and score them by cost, expected return, success probability, etc. This systematic analysis helps reach the most rational conclusion.

Self-Diagnosis Checklist for the Sunk Cost Fallacy

Is something holding you back right now? Use this checklist to objectively assess how deep you are in the sunk cost trap.

Sunk Cost Fallacy Self-Diagnosis Checklist

This checklist isn’t to criticize your decisions but to help you clearly recognize the psychological forces at work inside you. Honestly facing this mirror is the first step to change.

Giants Who Turned Failure into Opportunity: The Wisdom of Pivoting

The greatest skill to escape the sunk cost trap is not just cutting losses but finding new possibilities in failure’s ruins and boldly changing direction—pivoting.

• Success Story 1: The Birth of Slack: In 2009, Stewart Butterfield’s team poured years and millions into an online game called Glitch. But signs of failure were clear. Instead of clinging to sunk costs, they made a cold decision. Reviewing the failed project, they found value in an internal communication tool created to help team collaboration. They stopped game development and focused all efforts on this tool, which became the enterprise messenger Slack, later acquired for about $27.7 billion (38 trillion won).
• Success Story 2: Instagram’s Innovation: Instagram started as Burbn, a location-based check-in app with many features. Users barely used anything but the photo-sharing feature. Founders Kevin Systrom and Mike Krieger made a bold choice: drop all other features and focus solely on “taking, filtering, and sharing photos.” This pivot, treating past efforts as sunk costs, created Instagram, acquired by Facebook for $1 billion within two years.

Slack and Instagram’s stories go beyond just cutting losses. They coldly reevaluated the entire portfolio of sunk costs from failed projects and found the brightest assets no one noticed (Slack’s communication tool, Burbn’s photo sharing). This is the key difference between cutting losses and pivoting. Cutting losses answers “Should we continue this project or not?” Pivoting asks, “We abandon the original plan, but is there a seed for a new plan in what we’ve built?” It redefines failure as an opportunity for reallocation, a higher-level decision.

Say Goodbye to Past Costs and Choose Future Value

We’ve deeply explored the sunk cost fallacy, a psychological trap anyone can fall into. From the small habit of watching a boring movie to the trillion-won waste in national projects, this invisible force leads us to irrational decisions everywhere.

It’s not because you’re foolish or weak-willed. The strong instinct to avoid loss, pride in defending your decisions, and attachment to effort invested are deeply human emotions. The goal isn’t to become a perfectly rational robot. What matters is to recognize this trap exists inside us and consciously strive not to be controlled by it.

The tools introduced here—zero-base questioning, pre-mortem, opportunity cost analysis—will be your compass to step out of past ghosts, stand firmly in the present, and look toward the future. The past can’t be changed, but the future depends on your choices now.

The small courage to leave a boring movie early, the resolve to stop a hopeless project and seek new opportunities, the choice to end an unhappy relationship and prioritize your happiness—these are not signs of failure. They are the wisest and bravest beginnings of success, breaking free from obsession with past costs and choosing future value. Now, where will you invest your most valuable resources—time and energy?