Visible crew/equipment: After Anya teleports to the jail leaving Buffy and Xander in the forest, the shadow of cameraman walking backwards can be seen as Buffy and Xander make their way to Xander's car. Look closely, the shadow is visible and Buffy tells Xander not to be too sure about Anya being able to handle Willow tonight.
Continuity mistake: After Doris from Social Services leaves Buffy's house and Spike leaves after her, he takes his lighter out of Buffy's pocket. But earlier in the episode when everyone was packing away all of Willow's magic stuff, Buffy finds Spike's lighter and puts it in one of the boxes.
Tabula Rasa - S6-E8
Continuity mistake: When the gang is in the Magic Box and they pass out, we see Buffy fall on the floor at the top of the stairs, but in the next shot she has moved and is now lying on the steps.
Visible crew/equipment: In the scene where Anya is going over her wedding vows with Tara, she steps down from her dressing platform. As she steps down, part of the camera can be seen on the far left of the screen, obstructing the shot.
Character mistake: At the end, the new manager tells Buffy that the burgers are ground up veggies with rendered beef fat. But earlier in the episode, when Buffy finds the severed finger, it shows chunks of beef being ground up.
Continuity mistake: In the scenes where Buffy is being taught how to cook the burgers, the guy that is showing her has safety gloves on. In the close-up of the guy turning the burgers and pressing the buttons, the gloves are gone, and in the next shot, his gloves are back on.
Once More, With Feeling - S6-E7
Revealing mistake: When Buffy is singing in the Bronze with Anya and Tara as backup you can see Tara bump into the pillar and then dust herself off. (00:41:45)
Visible crew/equipment: In the final scene with Anya and D'Hoffryn the edge of the backdrop (and the set behind it) is visible when D'Hoffryn walks around her. (00:40:10)
Dead Things - S6-E13
Revealing mistake: In "Dead Things," after Buffy and Spike sleep together, when Spike asks, "Are we having a conversation?" and Buffy says, "What? No?" There is a side shot of her. If you look closely at her back (pausing helps), you can just barely see Buffy's skin colored tube top. Trust me, it's there. The time code is 1:22.
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.