You just let people do what they do and look at them and give them enough rope until they do what you thought they were going to do... which is screw you over.
Sam [L.Jackson] never asks for another take because he knows what he's doing. He gives you what he thinks is the best take, and he does it on the first take.
I'm sure there are a lot of Italians who refer to themselves as goombahs and greaseballs and whatever. That's what people do. It gives them a sort of familiarity that other people don't have.