In the original scene of Buffy fighting the telepathic demons in Earshot she said, “Say ‘Uncle.’ Oops. No mouth.” This was deleted from the episode in it’s final cut.

This conversation between Buffy and Willow was deleted from the episode Enemies:

Buffy: “I can’t stop thinking about that demon.”
Willow: “‘Cause of him being chopped up into little bits and all?”
Buffy: “Yeah, Will, let’s keep bringing on the visuals.”

A few lines were cut from the episode Doppelgängland:

Devon: “Hey, man, how’d you like to be our roadie?”
Angel: “Less than you’d think.”

and

Xander: “It’s all my fault.”
Giles: “What makes you say that?”
Xander: “I don’t know…Statistical probability.”

The episode Consequences had the following conversation between Angel and Faith cut:
Angel: “You and me, Faith, we’re a lot alike.”
Faith: “Well, you’re kind of dead…”
Angel: “Like I said. A lot alike.”
Faith: “Sorry, buddy. I’m alive and kicking. In fact, I’ve got a bodily function that needs attending …

This line of Buffy’s to Faith was deleted from the episode Bad Girls:
“I know you think you can handle this. And you’ve gotten used to being on your own. You’ve got your tough loner act down pretty well.”

Jack O’Toole’s line, “That’s it. No way am I bringing him back after I kill him” was deleted from the final cut of the episode The Zeppo.

This exchange between Buffy and Willow was deleted from the episode Helpless:
Buffy: “I mean, there’s a plus side to being a regular girl. The whole not-bleeding-and-killing-and-dying experience.”
Willow: “As for example.”
Buffy: “Then there’s buying outfits without worrying if they’re good for bleeding-and-killing-and-dying in. There’s a lot of good …

The following conversation between Amy and Willow was deleted from the episode Gingerbread:
Amy: “Oh, God, and Mr. Nyman that thing he does with his face…”
Willow: “The thing with the face! When he makes a point, the – I always think he’s going to sneeze!”
Amy: “I thought I was …

The exposition about Anyanka was changed in the episode The Wish. Giles’s original story of her ran as follows:
“Anyanka raised a demon to ruin her unfaithful lover. The demon did her bidding – but then cursed her and turned her into a sort of patron saint for scorned women. Apparently …

This line of Willow’s was cut from the episode Anne:
“Oh! That reminds me. I asked around about Andrew Hoelick, our gymnastic vampire, and apparently he used to like to hang out in Hammersmith Park and pick up grilles! Or, okay, that could be girls.”

This exchange between Buffy and Kendra was deleted from the episode What’s My Line? (Part 2):
Kendra: “Your English is very odd, you know.”
Buffy: “Yeah – it’s something about being woken by an ax. Makes me talk all crazy.”

This line of Spike’s to another vampire was deleted from School Hard: “Would it kill ya, a little mouthwash every couple hundred years?”

The following conversation between Buffy’s parents was deleted from the episode When She Was Bad:
Hank: “Oh, I’m spoiling her. Did I forget to mention that?”
Joyce: “What you forgot is that I’m gonna have to deal with another year of ‘Daddy would let me buy that.’”

The episode Nightmares featured the following line by Xander, “Okay, despite the rat-like chill that just crawled up my spine, I’m going to say this very calmly: Helllppp…”. This line was deleted from the final cut of the episode.

The following line of Xander’s was cut from the episode The Pack: “Welcome to the jungle”.