Thankfully, I have a background as an actor, and you learn how to live in that world of not knowing what's going to happen next.
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