I go with SB on Kay's stare after the Tahoe shooting.
Another really vicious one: Michael's stare in GF when he tells Sonny, "It's not personal, Sonny--it's business."

Ntra la porta tua lu sangu � sparsu,
E nun me mporta si ce muoru accisu...
E s'iddu muoru e vaju mparadisu
Si nun ce truovo a ttia, mancu ce trasu.