I think what makes a good actor's director is the same thing that makes a good director. Acting is just one of the trades necessary to make a movie.
“Real elation is when you feel you could touch a star without standing on tiptoe.”
“Music rhythms are mathematical patterns. When you hear a song and your body starts moving with it, your body is doing math. The kids in their parents' garage practicing to be a band may not realize it, but they're also practicing math.”