I think, first of all, you need to love what you're doing, and then this helps in the comedian for its part in everything-but the moment you enjoy what you're doing, you try to express yourself, to find your way, and every time is different, of course.
I think it has other roots, has to do, in part, with a general anxiety in contemporary life... nuclear bombs, inequality of possibility and chance, inequality of goods allotted to us, a kind of general racist, unjust attitude that is pervasive.