You've got to be in the moment and respond to what you're feeling. I try to simplify it as much as possible.
I think the best directors rarely loose their temper. I think the best directors provide you with a safe environment where they can instill you with confidence and allow you to try things out and not feel like your failing or that you're doing it wrong.
Most men have an insecurity of some sort. But we're brought up to believe that we can't show them.