Robin Williams has also tried to impersonate african americans, but he always knew how far he could go (and he's as over the top as you can get) :H also, he never used the N_ Word. Hotwater
The thing I've noticed when people of different races imitate someone of another race is that they will usually portray the more stereotypical side of those people. When whites imitate a black person they will usually play them as the street type and when blacks imitate whites it's usually the most stiff proper speaking suburban type. It's like you rarely see either group imitating each other in a variety of ways. Maybe this just shows how we all view each other in overly simple ways.
thats a fantastic social observation Motion(hey that rhymed! WOW), one that will have along lasting impact on my life and the lives of those i love