Suffering is not bad. If you understand it rightly, suffering is a cleansing. If you understand it rightly, sadness has a depth to it which no happiness can ever have. A person who is simply happy is always superficial. A person who has not known sorrow and has not known sadness, has not known the depths. He has not touched the bottom of his being; he has remained just on the periphery. One has to move within these two banks. Within these two banks flows the river.

— Osho


My thinking bent itself directly to the point I was attempting to master. I did not, however, accept it passively. If a theory convinced me, it did not remain an external, alien phenomenon; it altered my relationship with the world, and coloured all my experience.

— Simone de Beauvoir, from The Prime of Life: The Autobiography of Simone de Beauvoir; 1929-1944