How fashion trends develop

When Edward the VII could no longer button the bottom button of his waistcoat, elegant men in British society left their bottom buttons undone as a courtesy.

The other, even more important fashion he started, also by accident, was the crease in trousers; his trousers went into a shop after an accident on a trip, and the only ones his size had been stacked so strangely that folds ran down the front of each leg.

(found in an old issue of Punch)