SF isn't a genre; SF is the matrix in which genres are embedded, and because the SF field is never going in any one direction at any one time, there is hardly a way to cut it off.

The Gods do not protect fools. Fools are protected by more capable fools.

The Unexpected always comes at the most awkward times.

Fear is the brother of hate.

For each human being there is an optimum ratio between change and stasis. Too little change, he grows bored. Too little stability, he panics and loses his ability to adapt. One who marries six times in ten years won't change jobs. One who moves often to serve his company will maintain a stable marriage. A woman chained to one home and family may redecorate frantically or take a lover or go to many costume parties.

Building one space station for everyone was and is insane: we should have built a dozen.

The perversity of the Universe tends towards a maximum.