When you're starting out as an actor, you keep raising the stakes. First, you just want to be a character who comes on stage and gets a laugh or two and exits. Just five minutes on a stage, not even Broadway. But every time you say your little prayer at night, you place more demands.
I maintain that if you're a novelist and you go into an art museum, you'll come out a better novelist. And if you paint a picture for an hour you're a better actor at the end of it.
Rational behavior requires theory. Reactive behavior requires only reflex action.

