Everything I learned about snappy dialog I learned from Joss Whedon.
Cordelia: I don't mean to interrupt your downward mobility, but I just wanted to tell you that you won't be meeting Coach Foster, the woman with the chest hair, because gym was canceled due to the extreme dead guy in the locker.
Willow: What are you talking about?
Cordelia: Some guy was stuffed in Aura's locker.
Cordelia: Totally dead. Way dead.
Xander: It's not just a little dead, dead?
Cordelia: Don't you have an elsewhere to be?
Willow: Buffy has a really important date.
Giles: All right, I-I'll just jump in my time machine, go back to the twelfth century and ask the vampires to postpone their ancient prophecy for a few days while you take in dinner and a show.
Buffy: Okay, at this point you're abusing sarcasm.
Xander: Y'know, this might go a lot faster if you femmes actually picked up a shovel, too.
Giles: Hear, hear.
Buffy: Sorry, but I'm an old fashioned gal. I was raised to believe that men dig up the corpses and the women have the babies.
Anya: The power of the Wish made me a righteous sword to smite the unfaithful.
Xander: Well, hey! Good luck with that. Hope it works out for you.
Anya: You know, you can laugh, but I have witnessed a millennium of treachery and oppression from the males of the species, and I have nothing but contempt for the whole libidinous lot of them.
Xander: Then why you talking to me?
Anya: [averting her eyes] I don't have a date for the prom.
Xander: Well, gosh! I wonder why not. It couldn't possibly have anything to do with your sales pitch?
Anya: Men are evil... Will you go with me?
Xander: One of us is very confused, and I honestly don't know which.
Anya: When I lost my powers I got stuck with this persona, and now I have all these feelings. I don't understand it. I don't like it. All I know is I really want to go to this dance and I want someone to go with me.
Anya: Look, I know you find me attractive. I've seen you looking at my breasts.
Xander: Nothing personal, but when a guy does that it just means his eyes are open.
Anya: Whatever. Look, do you wanna go with me or not?
[Xander's eyes lower for a second, then flick back up to Anya's face.]
Olaf: You do well to flee, townspeople. I will pillage your lands and dwellings. I will burn your crops and make merry sport with your more attractive daughters.
Wash: “Yeah well, if she doesn’t give us some extra flow from the engine room to offset the burn through, this landing is gonna get pretty interesting.”
Mal: “Define interesting.”
Wash: “Oh god oh god we’re all gonna die?”
Mal: “This is the captain. We have a…little problem with our engine sequence, so we may experience some slight turbulence and then…explode.”
Jayne: “We’re gonna explode? I don’t wanna explode.”
Mal: “Kaylee, this is a place of business. We can talk about Simon-”
Kaylee: “When he’s four worlds away? Or the Alliance gets ahold of him and River?”
Mal: “That ain’t my worry. I gotta finish this job, get us another one. Can’t do that carryin’ those two.”
Kaylee: “How can you be so cold?”
Zoe: “Cap’n didn’t make them fugitives.”
Kaylee: “But he coulda made ‘em family. ’stead of keepin’ Simon from seein’ I was there. And I carried such a torch! And we coulda…goin’ on a year now and I ain’t had nothin’ twixt my nethers weren’t run on batteries!”
Mal: “Oh God! I can’t know that!”
Jayne: “I could stand to hear more.”
Mal: "Are you offering me a trade?"
Jayne: "A trade!? Hell, it's theft! This is the best damn gun made by man. It has extreme sentimental value. It's miles more worthy than what you got."
Mal: "What I got? She has a name."
Jayne: "So does this!" (caresses the gun lovingly) "I call it Vera."
Mal: "Well, my days of taking you seriously are certainly coming to a middle."
Zoe: "No one's gonna force you to go, Jayne. As has been stated -- this job's strictly speculative."
Jayne: "Good. 'Cause I don't know these folks, don't much care to."
Mal: "They're whores."
Jayne: "I'm in"
Jayne: "Shiny. Let's be bad guys."