Circumstances can force your hand. So think ahead!

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.

In handling a stinging insect, move very slowly.

He had learned that close-held secrets could often be cracked by going all the way to the top and there making himself unbearably unpleasant. He knew that such twisting of the tiger's tail was dangerous, for he understood the psychopathology of great power.

Each man is his own prisoner, in solitary confinement for life.

Physicians had gone to their graves calling Pasteur a liar, a fool, or worse—without examining evidence which their “common sense” told them was impossible.

Anything free costs twice as much in the long run or turns out worthless.