Here are some random selections from my collection of favorite quotes:

“In theory, there is no difference between theory and practice. In practice, there is.”
– Yogi Berra (has also been attributed to Jan L. A. van de Snepscheut)

“One test is worth a thousand expert opinions.”
– Unknown

“When cornered, an engineer will blurt out the truth.”
– Someone I used to work with at Ball Aerospace, in Boulder, CO

“It is usually futile to try to talk facts and analysis to people who are enjoying a sense of moral superiority in their ignorance.”
– Thomas Sowell

“The most merciful thing in the world, I think, is the inability of the human mind to correlate all its contents. We live on a placid island of ignorance in the midst of black seas of infinity, and it was not meant that we should voyage far. The sciences, each straining in its own direction, have hitherto harmed us little; but some day the piecing together of dissociated knowledge will open up such terrifying vistas of reality, and of our frightful position therein, that we shall either go mad from the revelation or flee from the light into the peace and safety of a new dark age.”
– H. P. Lovecraft, The Call of Cthulhu (I. The Horror in Clay), 1926

“Don’t go around saying the world owes you a living. The world owes you nothing. It was here first.”
– Mark Twain

“There is no worse tyranny than to force a man to pay for what he does not want merely because you think it would be good for him.”
– Robert A. Heinlein

“It has been said that politics is the second oldest profession. I have learned that it bears a striking resemblance to the first.”
– Ronald Reagan

“Unanswered questions are far less dangerous than unquestioned answers.”
– Unknown

“Never attribute to malice that which can be adequately explained by stupidity.”
– Robert A. Heinlein

“Research is what I’m doing when I don’t know what I’m doing.”
– Wernher Von Braun

“I once shook hands with Pat Boone and my whole right side sobered up.”
– Dean Martin

“Every man who says frankly and fully what he thinks is doing a public service.”
– Leslie Stephen