Never Kill A Boy On The First Date - S1-E5
Continuity mistake: The second time we see the van going towards Sunnydale, the creepy religious zealot guy puts his arm on the seat behind the mother and child. It then cuts to a closeup of them, and we cannot see the creep's arm behind them. It cuts back to a wideshot, and suddenly his arm is behind them again.
Never Kill A Boy On The First Date - S1-E5
Visible crew/equipment: When Buffy and Giles are in the cemetery, right before Buffy bails to go meet Owen, you can blatantly see a number rectangular studio/set lights reflected in Giles' glasses coming from various angles. (There wouldn't be dramatically-angled lights like that in a cemetery, let alone after dark).
Never Kill A Boy On The First Date - S1-E5
Continuity mistake: When Buffy gets up to walk over to Owen in the cafeteria, watch Willow and Xander... the directions they are facing change when it cuts to the wideshot. They suddenly are both watching Buffy in the wideshot, which they weren't before the shot cut. It's pretty subtle, so you have watch closely to notice.
Never Kill A Boy On The First Date - S1-E5
Continuity mistake: When Buffy, Xander and Willow are in the cafeteria in the beginning, Buffy says she's going to sit with Owen and Willow tells her "good luck." The way Willow is holding her fork changes between edits. (Specifically, it goes from pointed down to pointed up between cuts).
Never Kill A Boy On The First Date - S1-E5
Continuity mistake: When Buffy stakes the vampire in the opening scene, his arms go from up in the air to down by his sides between cuts right as she stakes him.
Continuity mistake: When Willow hides under the table in the classroom after fleeing The Pack, we see that it is on legs and doesn't touch the floor. Yet when Xander comes in and scans the room, he sees the table but Willow's feet aren't visible, even though they should be judging by the height of the table from the floor.
Continuity mistake: When Willow is unsuccessfully trying to tutor Xander outside towards the beginning of the episode, after Willow warns Xander he might flunk math, he reaches up and massages his face with his hand. When he does this, he has a pen in his hand. When the camera cuts to the opposite angle, the pen vanishes. Then, when the scene cuts to a wideshot about 10 seconds later, suddenly his hand is in a completely different position between cuts.
Audio problem: After Buffy catches the pig in the hallway, Principal Flutie tries to take him back. The pig squeals, making Flutie back up. However, it's painfully obvious that the pig isn't actually making the squeal and that it's just added in post. The pig looks completely calm and happy in Buffy's arms, it doesn't wriggle at all, and if you look closely, you can even see that its mouth doesn't move in the slightest. It's about as far away from squealing as possible.
Continuity mistake: When the zookeeper catches Buffy and Willow trying to sneak into the hyena exhibit in the beginning, when Buffy and Willow turn around, they get close to each other but there's still at least 6-8 inches of space between them. When the camera cuts, though, they are suddenly pressed literally right up against each other, to the point they are borderline huddling.
Deliberate mistake: When Xander ducks under the caution tape to catch up to the group of students at the beginning, as the shot is about to cut, judging by his casual walking pace, he should maybe be 10 or so feet ahead of Buffy and Willow. When the camera cuts, he's suddenly at least 30 feet away. It's probably edited that way for time reasons (to quicken the pace of the scene rather than show him walking an extra 10 seconds), but still a minor mistake.
Continuity mistake: When Buffy and Angel get to Buffy's house at the beginning, Buffy starts to use a first-aid kit to patch up Angel's wound. Angel's arm goes from down by his side to up on Buffy's shoulder between cuts. (It can be hard to see since it's close to the bottom of the frame, but it's noticeable. It seems like they cut out a few seconds to quicken the pace.) She's also a little bit closer to Angel between the same cut.
Continuity mistake: After Giles closes the library for "filing, " we see Buffy grab a crossbow off a shelf. It is upside down when she grabs it. Instantly between cuts, it is right side up. You can tell from the grip thingy that sticks out from it. (It looks like she starts to rotate it in the first shot, but it's instantaneously flipped over in the next).
Audio problem: At the beginning of the episode at the Bronze, when Buffy gets up to go and Willow tries to get Buffy to stay, Xander suggests they can dance. But his mouth movements don't match the words when he says "Eh, yeah, it's early..." (His head is turned away from camera, but you can see the side of his mouth, and he's saying something else).
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.