In the past, I'd sort of know before Ozzy sang something, what he was going to sing. I'd know what sort of way a melody was going to go 'cause of the way he'd approach it.
It doesn't matter who's directing, or who's doing the movie; there are a ton of things that can go wrong, and they do all the time. So you just have to figure out how to get through it, and then how the director finally puts it together, and then see what the audience takes from it. That's the most