>[!abstract] >*For want of a nail* is a proverb illustrating how small causes can have disproportionately large consequences through cascading effects. Originating in a medieval rhyme, it traces a chain of loss from a missing horseshoe nail to the downfall of a kingdom, showing how neglecting trivial details can trigger systemic failure. The phrase is widely used as a cautionary metaphor in management, engineering, and everyday life to emphasize vigilance over minor elements whose absence can compromise larger outcomes. ^ba05b1 >[!quote] >For want of a nail the shoe was lost; >For want of a shoe the horse was lost; >For want of a horse the rider was lost; >For want of a rider the message was lost; >For want of a message the battle was lost; >For want of a battle the kingdom was lost. >And all for the want of a horseshoe nail. >[!related] >- **North** (upstream): — >- **West** (similar): [[Nonlinear system]] >- **East** (different): — >- **South** (downstream): —