Even if you're improvising, the fact that beforehand you know certain things will work helps you make those improvisations successful. It really helps to have a certain amount of knowledge about musical structure.
A brave man is a man who dares to look the Devil in the face and tell him he is a Devil.
I may be compelled to face danger, but never fear it, and while our soldiers can stand and fight, I can stand and feed and nurse them.