At 35, I'm definitely starting to feel more like a grown-up than I ever have. There's nothing in my life that is childish or whimsical. Having fun is fantastic and I never want to lose a sense of that - and also, I think, you have to have that to put into your work or else it's going to feel stiff.
Art is longing. You never arrive, but you keep going in the hope that you will.
If I have enough ego to say I'm a writer, a director, a producer, and an actor, I should have the energy and the knowledge to write a scene for this great actor named Henry Fonda and direct him in it and have it work.