All the actor does is, he tries to get as many takes as he can out of the director that day. So he can walk away and say to himself, "Hey, it's in there. I'm not going to edit it. I'm not going to make those choices. If they want to blow it, it's fine. But I've done all I can." You're right. I'm always amazed when actors bash films as if those grips and that cinematographer didn't work hard enough.