Sunk Cost Fallacy

Surface

The sunk cost fallacy is the tendency to continue an endeavor because of previously invested resources, time, money, or effort, even when abandoning it would be the rational choice. The past investment becomes a psychological anchor.

Middle

Economists call past investments "sunk costs" because they cannot be recovered regardless of what you do next. Every decision should be based only on future costs and benefits. But human psychology is wired to feel loss acutely, abandoning something feels like admitting failure.

Deep

The sunk cost fallacy is why wars drag on, bad relationships persist, and failing projects get more funding. The rational question is never "how much have I invested?" but always "what is the best path forward from here?" The past is data, not a debt.