Wanted to share this story with you. My friend Kevin worked as production assistant and then eventually in casting, and one weird thing that he told me was lots of celebrities do not like for anyone to look at them in the eye. If an extra or any worker gives them eye contact, they will scream and cuss out that person in front of everyone, or on other occasions they will refuse to perform all together until that person has been ejected and/or fired. To this day he doesn't know why; he said they just F'N freak out like wild animals.
Anyone who acts like that is a loser, IMO. I'd never bow my head to anyone. I was taught to hold my head up and look people in the eye, I would never change that for a prima donna.