“Both optimists and pessimists contribute to society. The optimist invents the aeroplane, the pessimist the parachute.”

“To the optimist, pessimists are neurotic; to the pessimist, optimists are deluded.”

“Between the optimist and the pessimist, the difference is droll. The optimist sees the doughnut; the pessimist the hole! ”

“To the question whether I am a pessimist or an optimist, I answer that my knowledge is pessimistic, but my willing and hoping are optimistic.”

“Don't ever become a pessimist, Ira; a pessimist is correct oftener than an optimist, but an optimist has more fun--and neither can stop the march of events.”

“I tried to think about other things. I tried to invent optimistic inventions. But the pessimistic ones were extremely loud.”

“The optimist sees the donut, the pessimist sees the hole.”

“A stumbling block to the pessimist is a stepping-stone to the optimist.”

“I’m a pessimist because of intelligence, but an optimist because of will.”

“Sometimes a pessimist is only an optimist with extra information.”