Later on in that episode (Or maybe it's a different one... I'm not sure) a gun shot is heard and another gangster finds Johnny bleeding on the floor.
Gangster: What happend?! Did you get shot?!
Johnny: I ain't saying nothin'!!
Gangster: but what will I tell da' docter?
Johnny: Tell 'im suck a lemon!
The best quotes Simpsons have done is Bart's phone calls particually...
Bart: Is there a Mr. Jass there? His frist name's "Hugh"
Moe: Hang on! (Out loud) HUGH JASS!!! Yeah I'm looking for a Hugh Jass!! Someone check the men's room for a Hugh Jass!
Man: I'm Hugh Jass!
Moe: phone.
Hugh: (On phone) Hello this is Hugh Jass.
(Bart's face falls as his joke backfires on him)