experience

"Life can only be understood backwards but it must be lived forwards."

"The only source of knowledge is experience."

"Experience: that most brutal of teachers. But you learn, my God do you learn."

"Experience is simply the name we give our mistakes."

"A man who carries a cat by the tail learns something he can learn in no other way."

"It has been my experience that folks who have no vices have very few virtues."