I'd love for the US to move away from our bizarre tipping culture. However, if we do it'll remove one of the simpler douchebag cues we have.

Person who leaves exactly 15%: douchebag.

Person with leaves no tip: douchecanoe.

Person who leaves a penny: doucecraft-carrier USS Doucheprise.

Tipping is such an easy filter for the people you want to spend time with.