Continuity mistake: When Buffy comes in to talk to her mum about the CAT scan, we hear her shut the door behind her. We then cut to a shot of Buffy, and can see the door slightly ajar in the background. (00:10:30)
Continuity mistake: When Joyce is talking to Buffy about the shadow, after she says "sometimes weeks", she turns towards Buffy. In the next shot she's facing away from her, then turns to face her again. (00:10:55)
Revealing mistake: When Glory creates the demon snake thing, we see a CGI image of the creature, but Glory and Buffy are nowhere to be seen. When we are shown where they are standing, their position should have been visible when the snake demon was created. (00:27:05)
Visible crew/equipment: When Giles picks Buffy up in his car, you can see lighting and camera equipment on the right.
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.