"It is better to be unhappy and know the worst, than to be happy in a fool's paradise."

"Happiness does not lie in happiness, but in the achievement of it."

"The mystery of human existence lies not in just staying alive, but in finding something to live for."

"The best way to keep a man from doing something is to tell him he can't do it."

"Man is a mystery. It needs to be unravelled, and if you spend your whole life unravelling it, don't say that you've wasted time. I am studying that mystery because I want to be a human being."