Wednesday night, and question four on the Maths paper has already eaten forty minutes. The working cover half a page now. Crossed-out lines. A second method I start and abandon. The answer still does not come out clean. I know I should move on. I do not.
Business call this sunk cost. Money or time you already spent and cannot get back, no matter what you do next. The textbook example is always a factory that already paid for a machine. Whether they use it or leave it, the money is gone. The decision is only about what happens from now.
My forty minutes is the same. If I stop now, those minutes are spent whether I got the answer or not. If I keep going, I spend more minutes on a question that might still refuse to give me a clean result. The rational move is to skip to question five and come back if time allow. But skipping feel like admitting the forty minutes were waste, and that is uncomfortable enough to keep me at the same page.
Sunk cost trap is not only about Maths. Last month I spent two evenings on a commission sketch where the face kept looking wrong. I told myself I already invested so much colour that stopping now would throw it all away. So I kept adjusting. Two evenings become three. In the end the client was kind, but the file I sent was not better than the version from evening one — just more worked on. I paid extra hours for almost no improvement.
The hard part is emotional, not logical. Walking away from something you already put time into feel like the time meant nothing. But the time already happened. It is spent. The only choice left is what the next hour is for.
Art and Business teach the same lesson from different sides. In art, overworking a piece does not make it stronger. In Business, throwing more resources at a failing plan does not turn it into a good one. Both ask the same question: what is the best use of the time still in front of me, not the time already behind me.
Tonight I underline question four, leave a margin note that says “come back,” and start question five. The forty minutes do not come back. The next twenty go somewhere they might actually help.