10 quotes on optimism and pessimism

http://www.bbc.co.uk/news/magazine-23229014
"A pessimist sees difficulty in every opportunity. An optimist sees the opportunity in every difficulty" - Winston Churchill
"The man who is a pessimist before 48 knows too much; if he is an optimist after it, he knows too little" - Mark Twain
"The point of living, and of being an optimist, is to be foolish enough to believe that the best is yet to come" - Peter Ustinov
"Blessed is he who expects nothing, for he shall never be disappointed" - Alexander Pope
"A pessimist is a person who has had to listen to too many optimists" - Don Marquis
"An optimist may see a light where there is none, but why must the pessimist always run to blow it out?" - Rene Descartes
"The basis of optimism is sheer terror" - Oscar Wilde
"No pessimist ever discovered the secret of the stars, or sailed to an uncharted land, or opened a new doorway for the human spirit" - Helen Keller
"I'm a pessimist because of intelligence, but an optimist because of will" - Antonio Gramsci
"I like pessimists. They're always the ones who bring lifejackets for the boat" - Lisa Kleypas
Source: Goodreads, Brainyquote, Jimpoz