Since somebody already mentioned "Snatch", I'll post Lock Stock & Two Smoking Barrels. Great quotes in both movies, especially the gun monologue in Snatch.
Eddie: They're armed.
Soap: What was that? Armed? What do you mean armed? Armed with what?
Eddie: Err, bad breath, colorful language, feather duster... what do you think they're gonna be armed with? Guns, you tit!
Rory Breaker: If the milk turns out to be sour, I ain't the kinda pussy to drink it.
Tom: Rory Breaker?
Barfly Jack: Rory? Yeah I know Rory. He's not to be underestimated, you've got to look past the hair and the cute, cuddly thing - it's all a deceptive facade. A few nights ago Rory's Roger iron's rusted, so he's gone to the local battle-cruiser to catch the end of his footer. Nobody is watching the custard so he turns the channel over. A fat man's north opens and he wanders over and turns the Liza over. 'Now #### off and watch it somewhere else.' Rory knows claret is imminent, but he doesn't want to miss the end of the game; so, calm as a coma, he stands and picks up a fire extinguisher and he walks straight past the jam rolls who are ready for action, then he plonks it outside the entrance. He then orders an Aristotle of the most ping pong tiddly in the nuclear sub and switches back to his footer. 'That's ####ing it,' says the guy. 'That's ####ing what' says Rory. Rory gobs out a mouthful of booze covering fatty; he then flicks a flaming match into his bird's nest and the man's lit up like a leaky gas pipe. Rory, unfazed, turned back to his game. His team's won too. Four-nil.