It wasn't me, it was my manager who got the insult, and it was damn near pure poetry.
I don't even remember the incident too clearly because the insult overshadowed everything. I think that both my manager and I were trying to explain to this woman that her I.D. pegged her as too young to buy... cigarettes or booze, don't remember which...
My manager finally told her to leave, and she yelled, "Shut up you syphilitic cum junkie," before storming out.
We looked at each other and I said, "Damn, that was beautiful. She didn't even stutter once while saying that."