The Pesci character in Casino was based on a real guy. And he really was that crazy. What was Pesci suppose to do? Perhaps he should of not taken the roll, but I am guessing he took it, because of Martin.
Well he definitely dehumanized plenty of his kills. The way he talked about killing the guys with beach balls, and his longest shot was kind of disturbing. He spoke so nonchalantly about it. Who knows though? He did do a bunch of tours.