The episode with the drunken gunsmith. The end with Vash and the barkeeper.
Vash: AHAHAHAHA! HEY GRANDMA WHATCHA WAITIN FOR, FILL ER UP!
(Barkeeper bonks him over the head with a beer pitcher)
Vash: I mean please fill er up miss, if you wouldn't mind.
Barkeeper: That's better.
- Earlier in that same episode:
Vash (who's drunk off his gourd): Gimme...gimme back mah gun grandma...(gets hit in the face with his gun) * THWACK!*
Frank Marlon: What happened, brother?
I dunno, my head just started to hurt.
- And he still catches his gun!