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.
“Workers of France, it is for the freedom of the prisoners that you will go to work in Germany! It is for our country that you will go in large numbers!”
“Well, you sort of get out of the pool room, you get out of the Marine Corps, you get out and read some literature, you become involved with people who also want to know and are ready to share some ideas about literature and thoughts, and it becomes nourished that way.”