Experience is valuable only when it has brought suffering and when the suffering has left its mark upon both body and mind. Sleepless nights and conflicts with reality make statesmen realists; how could these experiences be usefully handed on to young idealists who expect to transform the universe without effort? The counsels of Polonius are platitudes, but the moment we start giving advice we are all like Polonius. For us those platitudes are packed with meaning, memories, and visions. For our children, they are abstract and boring. We should like to make a wise woman of a girl of twenty; it is physiologically impossible. "The counsels of old age," said Vauvenargues, "are like a winter's sun which gives light but no warmth."

Un Art de Vivre (The Art of Living) (1939) - The Art of Family Life