Although I disapprove of your "Patronizing" tone of the question, I will not disappoint.

I wouldn't say he's my favourite but I do admire his character to an extent similar to that I do for Vito Corleone. That character I'm mentioning would be THE DEVIL, otherwise known as Kaiser Soze. It was the main "bad guy" in "The Usual Suspects". I'm not sure if he qualifies as "Mafia" since he's not Sicilian, but still he amazes me.

Another one could be the character of Max played by James Woods in Once Upon a Time in America.

That's it for now, I'll come back if I remember anything different.

"..Your youngest and strongest will fall by the sword.."

"...now you gotta speak more than one language to pull a heist..." Pudge Nichols

"...Never shall innocent blood be shed; yet the blood of the wicked shall flow like a river. The THREE shall spread their blackened wings and be the vengeaful striking hammer of God..."