I made a very important discovery at Camp Currie. Happiness consists in getting enough sleep. Just that… — Robert A. Heinlein

I made a very important discovery at Camp Currie. Happiness consists in getting enough sleep. Just that, nothing more. All the wealthy, unhappy people you've ever met take sleeping pills; Mobile Infantrymen don't need them. Give a cap trooper a bunk and time to sack out in it, and he's as happy as a worm in an apple—asleep.

p. 52Source: Wikiquote · CC BY-SA 4.0