What is your favourite quote?

I found some of these quotes very interesting.

The time to stop talking is when the other person nods his head affirmatively but says nothing.
Henry S. Haskins

Humor is a rubber sword - it allows you to make a point without drawing blood.
Mary Hirsch

There are two ways to slide easily through life; to believe everything or to doubt everything. Both ways save us from thinking.
Alfred KorzybskiUS (Polish-born) author, logician, & scientist (1879 - 1950)