Why does sunk cost trap commitments fail?

The most common reason sunk cost trap commitments fails: Overcorrecting into premature abandonment — using 'sunk cost fallacy' as an intellectual excuse to bail on commitments the moment they get difficult. Not every hard stretch is a sunk cost trap. Some commitments require sustained investment through discomfort before they pay off. The failure mode is learning the phrase 'sunk cost fallacy' and then wielding it as a rationalization to quit anything that demands patience. The real skill is distinguishing between a commitment that is genuinely dead and one that is merely in its difficult middle.

The fix: Identify one commitment you are currently maintaining primarily because of what you have already invested in it — time, money, reputation, emotional energy. Write down two lists side by side. List A: everything you have already put into this commitment (the sunk costs). List B: what continuing this commitment will realistically produce in the next 6 months, assuming the same trajectory. Now cover List A with your hand and read only List B. If a stranger saw only List B, with no knowledge of your history, would they advise you to start this commitment today? If the answer is no, the sunk cost is the only thing holding you in. Name that honestly.

The underlying principle is straightforward: Past investment does not justify continuing a commitment that no longer serves you.