You've been dating someone for five years. The spark died two years ago. You're staying because you've "invested so much time." Sound familiar? You're not being romantic—you're being irrational.

The sunk cost fallacy has you trapped, and it's costing you more than you think.

What the Hell Is a Sunk Cost, Anyway?

A sunk cost is money, time, or effort you've already spent and can't get back. Economists say these costs should be irrelevant to your current decisions. What's done is done. The only rational question is: what's best moving forward?

But we're not rational creatures. We're emotional ones.

The sunk cost fallacy is our stubborn tendency to keep throwing good time after bad. We continue with jobs we hate, relationships that drain us, and projects doomed to fail—simply because we've already invested so much. Walking away feels like admitting defeat. Like all that effort was wasted.

Here's the brutal truth: it was wasted the moment you realized it wasn't working. Every day you stay is just wasting more.

The Concorde: A $100 Million Lesson in Stubbornness

In 1956, French and British manufacturers started building the Concorde supersonic airplane. Initial estimates? Nearly $100 million. As costs ballooned and financial projections turned grim, both governments faced a choice: cut losses or keep going.

They kept going. Not because it made economic sense, but because they'd already invested too much to quit. The project became known as the "Concorde fallacy."

The plane flew for less than 30 years. It never turned a profit.

This wasn't unique to governments or corporations. We all do this. Every single day.

Why Our Brains Can't Let Go

Several psychological forces conspire to trap us:

Loss aversion hits hardest. Losses hurt roughly twice as much as equivalent gains feel good. Admitting we've wasted five years in a dead-end job feels unbearable. So we waste six years instead. Then seven.

Commitment bias means we'll bend reality to support past decisions. We invested all that time for a reason, right? So we construct narratives that justify staying, even as evidence mounts that we should leave.

The narrative of failure haunts us. If we quit, the story becomes: "I failed." If we persist, maybe—just maybe—the story ends with redemption. We prefer uncertainty to certain failure, even when uncertainty means prolonged misery.

Research shows we're particularly action-oriented when facing escalation decisions. When things go wrong, we feel compelled to do something—and "doing something" usually means doubling down, not walking away.

The Relationship Trap

You've been together for years. You've met each other's families. You've talked about marriage, kids, the future. But something's off. You're not happy. Haven't been for a while.

The thought of leaving is terrifying. All those memories. All that time. The shared apartment, the merged friend groups, the joint Netflix account. Walking away means admitting those years "didn't matter."

But here's what we systematically get wrong: We overestimate how painful the breakup will be today. We underestimate how painful staying will be over years and decades.

A 2018 study found people remain in unhappy relationships primarily to avoid inflicting pain on their partners. Noble? Maybe. But you're also inflicting pain on yourself—and your partner probably knows you're unhappy anyway.

Deep emotional bonds make this worse. Even toxic relationships have good moments. Those memories act like anchors, keeping us tethered to a sinking ship.

External pressure multiplies the effect. Friends and family expect you to "work it out." Society tells us long-term relationships are inherently valuable, regardless of quality. Every year you stay, you're not just losing time with the wrong person. You're losing the opportunity to find the right one.

That's the real sunk cost: the good relationships you're sacrificing for the bad one you can't abandon.

Career Quicksand

You spent four years getting an engineering degree. Graduated with honors. Landed a solid job. But three years in, you realize you hate it. The work bores you. The culture drains you.

You've always wanted to paint. But switching now? That would mean all those years of school, all that tuition, all that career building was "for nothing."

So you stay. One more year becomes five. Five becomes ten. You're good at engineering, even if it makes you miserable. You've climbed the ladder. Changing careers now means starting over.

This is commitment escalation in action. The more you invest, the harder it becomes to walk away. Each year adds weight to the anchor dragging you down.

Companies and governments do this with failing projects all the time. Employees and managers feel pressure to "make it work" because admitting the initial investment was a mistake feels impossible. So they pour in more resources, chasing losses like gamblers at a casino.

Educational institutions keep ineffective programs running. Why? Because discontinuing them means acknowledging the time and money already spent achieved nothing.

The pattern is universal. The consequences are profound.

The Math Doesn't Care About Your Feelings

Barry Staw's landmark 1976 study first documented escalation of commitment. People systematically allocated more resources to losing investments. Not because the fundamentals improved, but because they'd already invested.

Arkes and Blumer's 1985 research cemented the framework. They showed people irrationally factor in irrecoverable costs when making present decisions. Again and again, participants chose poorly because they couldn't ignore sunk costs.

Four experiments published in Psychological Science confirmed people facing escalation decisions are intensely action-oriented. When things go wrong, doing nothing feels worse than doing the wrong thing.

This makes evolutionary sense. Our ancestors who gave up too easily didn't survive. Persistence was adaptive. But our environment has changed faster than our brains. The persistence that helped us survive the savanna now traps us in soul-crushing jobs and loveless marriages.

The Question That Changes Everything

Rational decision-making requires focusing only on future costs and benefits. What you've already spent is irrelevant. It's gone. The only question is: what's best from this point forward?

Here's the magic wand test: If you could guarantee no regrets, what would you choose today? Not what justifies yesterday. What's best for tomorrow?

If the answer is "leave" but you're staying anyway, sunk costs have you trapped.

Recognizing this isn't admitting failure. It's reclaiming agency. Every investment teaches you something, even if it didn't work out as planned. Those five years in the wrong relationship taught you what you actually need. That engineering degree taught you what fulfills you (and what doesn't).

Energy spent is never truly wasted if you learn from it. But the learning only helps if you act on it.

Breaking Free

Start by reframing the narrative. Leaving isn't failure—staying when you shouldn't is. Walking away isn't quitting—it's choosing your future over your past.

Ask yourself: If I started today with zero investment, would I choose this relationship? This career? This project? If the answer is no, your sunk costs are making the decision for you.

Consider what economists call opportunity cost: What are you missing while you're stuck here? What relationships, careers, or experiences are you sacrificing to avoid admitting this one didn't work?

The pain of change is intense but brief. The pain of staying is tolerable but endless. We're wired to prefer the second option. But wiring isn't destiny.

Your past investments don't obligate your future. They inform it. The question isn't whether you can afford to leave—it's whether you can afford to stay.

The Concorde flew for 27 years. It never should have flown at all. Don't be the Concorde.