How do you react when ........?

[Gavin Greenwalt]

If a director has to remind someone of his/her position, they're not doing a great job directing in the first place.

Mmmmm... yes and no. To play devil's advocate I've seen a lot of power struggles over idiotic stuff from clueless staff/crew. When you're directing, supervising or in some leadership position a good leader will of course be open to input and discussion--but at some point someone has to make a decision and move on--and that decision (unless unsafe) needs to be final. I've seen and experienced a lot of unprofessional cases where someone is still pressing the point and you just have to go "Thank you for your input, you've made your peace, but we're doing XYZ instead--drop it."

I've seen power freaks too who have to constantly knock down people to feel powerful but there's also those who have delusion of grandeur and seem more interested in doing someone else's job.