Continuity mistake: In the final scene with Buffy and Willow at the end of the episode, the position of Buffy's right bra strap keeps changing throughout the entire scene.
Visible crew/equipment: After Gnarl poisons Dawn and traps Willow inside his cave, the shadow of a camera is visible on some bushes on the left side of the screen as we see Xander and Buffy carrying Dawn home.
Other mistake: We're shown a variety of photographs and pictures of different members of the gang at one point. One of those, the one of Xander and Anya, is actually a shot from the episode "Something Blue". I doubt very much that during the events in that episode, someone conveniently decided to take a photograph.
Visible crew/equipment: When a guy asks Dawn out to Winter Formal and she says "What?" - you can see a microphone at the top of the screen. (00:33:35)
Continuity mistake: When Cassie and Dawn were talking, just before Cassie got kidnapped, Cassie put her hand on Dawn's shoulder, but in the next shot, her hands were by her side.
Continuity mistake: Towards the end, when Buffy stops the arrow, when she first grabs it her hand drops down to Cassie's mouth level, and her arm's bent at the elbow. When we cut to another angle it's now held at arm's length and at about eye level.
Revealing mistake: When Anya sings her song about how she will become Mrs. Harris, she spins Xander's chair around after putting a blanket on him. When she is also sitting on the chair, and you see an overhead shot of them both, you can see a section of the stage floor rotating beneath them keeping the chair spinning.
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.
Continuity mistake: When Dawn is in Principal Woods' office to talk about the accident, she gets up and leaves. Her bag is still hanging from the chair, but she has it in the next scene.
Visible crew/equipment: During the scene where Willow and Anya fall in love with RJ after he visits Buffy's house, and everyone but Dawn runs off to do their thing, the camera pans to Dawn and a woman with a maroon, long sleeved shirt is briefly visible standing on the stairs to Dawn's right.
Continuity mistake: When Anya is sneaking into Spikes room after she closes the door the shot goes to spike and the sheet is lying square across his stomach and the camera goes back to Anya she then walks over to the chest of drawers and we see spike in the shot and the sheet is now lying at an angle so we can see his hip.
Audio problem: When Buffy is about to close the door as she goes into the bathroom, it actually never closes. But we still hear the sound of the door closing. (00:15:20)
Other mistake: When Buffy is talking about Spike's trigger she says, "He's a bomb and I need to know how to defuse him." The DVD subtitles misspell "defuse" as "diffuse." (00:23:55)
Other mistake: When Buffy pulls the knives out of the Bringers, there is no blood on them. Also, you can see the muscular arm of Buffy's stunt double pushing the knives into the Bringers. (00:34:00)
Revealing mistake: As Buffy throws Spike into a wall after he bites Andrew, Spike's stuntman is visible in-shot. His hair is slightly different to James Marsters'.
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.