Once More, With Feeling - S6-E7
Visible crew/equipment: When Buffy kicks the front door of The Bronze down to confront Sweet and save Dawn, a cable can be seen attached to the door used to pull it down.
Where The Wild Things Are - S4-E18
Visible crew/equipment: When Xander and Anya pull over in the ice-cream van, the front windscreen is very reflective. To avoid reflecting the camera crew, a giant screen was put in front of the ice-cream van - which, ironically, is reflected in the windscreen. It isn't a reflection of another vehicle parked in front of them as the thing that is reflected is a curved shape.
Visible crew/equipment: When Buffy, Willow and Anya are watching Looney Tunes, some stage lights are reflected in the globe behind Willow.
Seeing Red - S6-E19
Visible crew/equipment: When Buffy says, "Goodnight, bitch" to Warren, right before she kicks him it is quite obvious that it is his stunt double.
Continuity mistake: When Buffy falls down after the Master bites her, you can see her fall, then hear her hit the dry ground. But then a few shots later she falls again and this time into water.
Audio problem: When Warren, Jonathan and Andrew break into the museum to get the diamond, Warren makes a hole in the glass, then pushes it through, but when it lands, it sounds like plastic, not glass.
Continuity mistake: When the detective is interviewing the woman in the alley, he mentions that the murder took place "last night". In "Bad Girls", we see Buffy visiting Faith the day after the murder, and that night is presumably when she has the dream about drowning, so by the time the detective is asking this question it is actually two nights after the murder, not one.
I Only Have Eyes For You - S2-E19
Visible crew/equipment: When Xander opens his locker and the gross hand grabs him, if you use slow-mo when the shot is inside the locker looking out, you can see the white t-shirt of the man whose arm it is. (00:10:20)
School Hard - S2-E3
Continuity mistake: When Buffy and Willow are studying at the Bronze, the position of Buffy's pencil changes between shots after they leave their table to go dance. Nobody else goes to their table between these shots.
Other mistake: Willow's computer beeps twice when her first email from Malcolm is received through before she is kidnapped by Fritz, but only beeps once when the second email is received.
Lies My Parents Told Me - S7-E17
Revealing mistake: When Spike tells his mother that he's become a vampire, she asks him if he's drunk. He responds with "Little bit." Just after he says this, someone can be heard coughing off-camera. It could be his mother because she isn't supposed to be well, but it seems odd that the camera wouldn't be on her during this. And a cough wouldn't really be necessary for the scene.
Continuity mistake: At the beginning of the episode Buffy is thrown against a 'No Trespassing' sign and the sign is all crinkled, the vampire also punches it but later in the episode we see the same sign except that it looks brand new.
After Life - S6-E3
Continuity mistake: When Dawn and Buffy were talking in Willow and Tara's room, Dawn's necklace went from being above her top, to underneath her top.
School Hard - S2-E3
Revealing mistake: When Spike is talking to the Anointed One for the first time, one of the henchmen tries to rush him from behind and Spike backhands him without even looking, but Spike's hand movements, the reaction of the henchman and the sound of the punch connecting on the audio track are all out of sync.
Visible crew/equipment: In the scene where the demons are attacking, one of the demons throws Buffy across a table. If you look carefully, you'll see the black mat which softens the stunt double's fall on the floor when she hits the ground.
Continuity mistake: When Wesley and Cordelia kiss, after a few seconds they freeze in place. Cordelia has her left arm around his waist, we see a shot of her face for about a second with her arm definitely angled downwards, then we cut to Wes' face and her hand's now on his neck. (00:25:20)
Chosen answer: Angel is saying that he is still jealous and Buffy recognizes that this is his way of saying he wishes that they could be together. That is why they both smile.