I never understood what was so funny about that. Buffas? Am I missing some slang meaning of the word?

These are my favourites:

1)When Frankie, at the beginning of GF2 says "A kid comes up to me in a white jacket, gives me a Ritz cracker, and uh, chopped liver, he says Canapés. I say uh, uh, can o' peas my ass, that's a Ritz cracker and chopped liver! " That always makes me laugh. Can of peas.

2)When Geary says to Willy Cicci "Uh -- Mr. Cicci could you, uh -- amplify your answer a bit?" The way Cicci just says in his 'gangster' accent "Do what?".

3)In GF3 when Vincent says "Well you tell him from me that he can live or he can die!", and Mike just loses his temper and roars "Vincent will you SHUDDUP!"
Also the way Michael jumps when Vincent snaps "RIGHT??!" in the first Zasa scene.