The instinct that pulls us toward art is the impulse to evolve, to learn, to heighten and elevate our consciousness. The Ego hates this. Because the more awake we become, the less we need the Ego.
I tend to arrive in the rehearsal process with very strongly developed ideas about what I want to do. But I don't like those ideas to be things that are not subject to change, or subject to development, or subject to challenge.