Chimps, thanks for that "I'll kill your dog!" reminder. That was mean but it worked and the same shit happens today between major directors and their major stars which eventually gets the best on-screen performance.
I've been on a number of movie sets where major actors perform amazing acting roles and it damn-right fascinating to say the least.
Ten minutes before a major scene you're talking to this nice guy over a cup of coffee and a doughnut and minutes later he's a deranged serial killer in front of that PanaVision camera completely convincible and completely different from his real personality.
I have two family members in the movie acting business and sometimes they 'become' the person they will be portraying on screen at home while spending time with the wife and kids..... and at times, it's downright scarey and very fascinating - especially if he's rehearsing for a serial killer type role coming up. Then the kids all beg him to stop and become their dad once again, or maybe that friendly monster he portrayed last year in Costa Rica.
But they kids at home and up and down the block really love him when he's casted in Planet of the Apes roles (two so far) because they love to climb trees and run up and down the street on all-fours and peel bannanas like a monkey.
And he can immediately change his personality to become any actor you've most likely seen on any movie screen. Good actors really have amazing talent on the screen and off as well.