There will always be survivors.

It takes two to create a heaven, but hell can be accomplished by one.

Tilting at windmills hurts you more than the windmills.

The second best thing about space travel is that the distances involved make war very difficult, usually impractical, and almost always unnecessary. This is probably a loss for most people, since war is our race's most popular diversion, one which gives purpose and color to dull and stupid lives. But it is a great boon to the intelligent man who fights only when he must-never for sport.

Do-gooding is like treating hemophilia - the real cure is to let hemophiliacs bleed to death...before they breed more hemophiliacs.

Moving parts in rubbing contact require lubrication to avoid excessive wear. Honorifics and formal politeness provide lubrication where people rub together. Often the very young, the untravelled, the naive, the sophisticated deplore these formalities as 'empty,' 'meaningless,' or 'dishonest,' and scorn to use them. No matter how 'pure' their motives, they thereby throw sand into machinery that does not work too well at best.

On two subjects the overwhelming majority of people regarded their own opinions as Absolute Truth, and sincerely believed that anyone who disagreed with them was immoral, outrageous, sinful, sacrilegious, offensive, intolerable, stupid, illogical, treasonable, actionable, against the public interest, ridiculous, and obscene. The two subjects were (of course) sex and religion.