Achilles Effect

Achilles was dipped in the river as a child and made invulnerable — everywhere except the heel by which his mother held him. One arrow, one heel, and the greatest warrior of the age fell.

The principle underneath: a thing does not fail at its strongest point, nor at its average point. It fails at its weakest point. A chain is exactly as strong as its worst link, and no stronger.

So it is with plans, companies, and characters. A brilliant strategy with one unchecked assumption is a heel. A disciplined life with one neglected habit is a heel. We polish our strengths because polishing is pleasant; the weak spot is where the arrow lands.

Ask of anything you build: where is the heel? Find it while it is still a small tenderness. Guard it before it becomes the famous part of your story.