Improvisation is at the heart of starting, mainly because it requires a decisive, intuitive, transactional reaction. We must take great interest in the moment and bite into a fight-or-flight situation.
The more prepared we are in skill level precedes our creative reaction to the prompt, whether it be a jazz cue or comedy session.
Playing in such activities, dancing with the doubt and fears, is an entirely intelligent process. Like the octopus, we hanker for the inchoate response. And then find out where the tune goes.