Continuity mistake: When Xander's being threatened, the knife moves from under his chin to the side of his neck between shots.
Revealing mistake: When Tara is being chased by the monster and she falls, she says a spell and white smoke comes out of her hands but it is coming out of the sleeves of her shirt, the way she holds her hands up suggests this as well.
Continuity mistake: In the kitchen scene Buffy takes the pizza out of the fridge and closes the door, but in the next shot the door is open and two shots later it's closed again.
Continuity mistake: When Buffy sat down on a car and set off the car alarm, she didn't have any dirt on her hands and only a little bit of blood, but in the next shot, there was a lot of blood and dirt on her hands.
Other mistake: At the end of the episode Willow mentions going to the Bronze on a Wednesday night, Buffy also mentions to Giles that she got almost everyone killed on the second day of school. From the different clothing being worn each day, it's obviously been more than 2 school days and should instead be Thursday by the end of the episode.
Storyteller - S7-E16
Audio problem: After Anya and Xander sleep together again, Anya says "I think, maybe we're really over. Which - it's good, right? I mean, now we can move on." When she says "Which - it's good", her lips don't match what she's saying.
Continuity mistake: When Buffy ties Spike to a chair before the opening credits, she ties a rope around his left arm three times. But two extremely fast shots later, the rope is tied around his left arm four times.
Continuity mistake: In the flashback to St. Petersburg, 1905, just after the burning man runs out of the room, Halfrek mentions the Revolution. Between shots, Anya's champagne glass switches from her left hand to on the table and back.
As You Were - S6-E15
Continuity mistake: When we see Xander and Anya going over the seating arrangements for their wedding, Xander is eating from a large sack of crisps. During the conversation Anya takes them off him, he takes them back and places the bag next to him. We see the bag after Xander puts it down, and in a closeup shot of him, the front of the bag is facing upwards. But when Dawn comes in, the front of the bag is facing downwards - barcode and ingredients are visible.
As You Were - S6-E15
Continuity mistake: At the beginning of the episode when Buffy offers Dawn another burger from Doublemeat Palace, she is holding the burger in her hands just before Willow comes in with her line, "Hey, workin' lady. Rough night?" The burger then jumps from the kitchen counter to Buffy's hands between shots.
Tabula Rasa - S6-E8
Continuity mistake: When Buffy and Spike (as Joan and Randy) are fighting Bro'os vampires, Buffy kicks down a post box to stake one of them. The pole supporting the post box breaks away at a jagged angle. But when she uses it to stake one of the vampires the end that she uses has suddenly changed to the traditional triangular point, only to return to its original jagged angle immediately afterwards. The shot of her staking the vampire is not a side angle of some uneven ends. Watch as she backs away from the vampire after he's been staked, it is a fully triangular point.
Life Serial - S6-E5
Visible crew/equipment: When Xander is talking to Buffy about blacking out and evil lint before introducing her to the foreman at the construction site, a crew member can be seen walking behind them holding up an anti-glare screen. (Only visible in widescreen.)
Continuity mistake: When Oz turns back into a werewolf, he chases after Tera. She hits him with a chair and he falls to the ground and passes out. We then see The Initiative show up and learn that Riley has shot Oz with a dart (it's sticking out of Oz's side). But two shots earlier the dart wasn't there.
Visible crew/equipment: At the end when the gang leave the high school, stage lights are reflected in the broken glass of the double doors that they exit through.
Continuity mistake: When Oz shows up at Buffy and Willow's dormitory, Willow has a lump or a pimple above the left corner of her mouth. It disappears later in the episode when she's talking to Buffy about her feelings for Tara and it returns at the end when she and Oz are in his van.
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.