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.
“One of my producers said this business is like a hamster on that little wheel thing that goes around and around. You may have a great day and get great ratings, but then you've got another show to do - whatever moment of success or happiness you have you've got to keep grinding it out for the next d”