I like that "pre-horsehead" scene with Robert Duvall:
Tom Hagen: You're gonna have some union problems; my client could make then disappear. Also, one of your top stars has just moved from ah marijuana to heroin...
Jack Woltz: Are you trying to muscle me?
TH: Absolutely not.
JW: Now listen to me, you smooth-talking son-of-a-bitch! Let me lay it on the line for you and your boss, whoever he is. Johnny Fontane will never get that movie! I don't care how many dego guinea W.O.P. greaseball gumbahs come out of the woodwork!
TH: I'm German-Irish
JW: Well let me tell you something my Kraut Mick friend, I'm gonna make so much trouble for you, you won't know what hit you!
that's normally the point where a Mick would find a glass object close by and try and stab your pancreas...but Tom held his anger. Boo Radley all grown up.