You don't stop laughing because you grow old. You grow old because you stop laughing.
I feel about airplanes the way I feel about diets. It seems to me they are wonderful things for other people to go on.
A boy can learn a lot from a dog: obedience, loyalty, and the importance of turning around three times before lying down.
There is still a difference between something and nothing, but it is purely geometrical and there is nothing behind the geometry.
Reveal not every secret you have to a friend, for how can you tell but that friend may hereafter become an enemy. And bring not all mischief you are able to upon an enemy, for he may one day become your friend.
Most advances in science come when a person for one reason or another is forced to change fields.
All programmers are playwrights and all computers are lousy actors.