Visible crew/equipment: After Tara is found in the Janitor's closet and brought back to her room as Willow & Buffy come in, there is a mirror to the left of the door. It has a scarf draped over it to prevent it from reflecting things it shouldn't, but the bottom right corner is still exposed and in it you can see glimpses of the crew moving around behind the camera.
Visible crew/equipment: When Buffy, Willow, Xander and Giles all agree that Morgan is their one suspect, a camera and a cameraman can be seen in the reflection of the glass in the door labeled "Librarian", right after Buffy says, "Uh, priority check, Giles." A boom mic is also reflected in the top right of the glass when Buffy finishes her line with "talent show murder!" The mic can be seen throughout the rest of the scene from two different camera angles.
All The Way - S6-E6
Visible crew/equipment: A boom mic is reflected in the window of Buffy's house when she and Xander sit outside discussing his engagement to Anya.
Where The Wild Things Are - S4-E18
Visible crew/equipment: While the house is becoming "Wild", Riley takes Graham down to The Initiative. Once the door closes behind them and the mirror returns to its original position, the shadow of a camera is reflected in the mirror. It's in the middle of the frame, on the left, over a book case.
Visible crew/equipment: In the scene at Buffy's house, her mum comes into her room and says "Buffy, I'm home". As she says this a boom mic is visible above her head.
I Only Have Eyes For You - S2-E19
Visible crew/equipment: After the history teacher writes, "Don't walk away from me, bitch!" on the chalk board, Buffy says to Xander, "I'm telling you, something weird is going on." As she says "something", a boom mic is reflected in the window behind her on the right.
Visible crew/equipment: In the episode 'This Year's Girl', when the Scoobies find the demon in the woods that Adam has cut open you can see a boom mike operator in the background. (00:07:40)
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.
Visible crew/equipment: When the Scoobies are attempting to leave Buffy's house by using magic, we see a close up shot of the house's front door knob. None of the Scoobies are reflected in the door knob even though they're standing right in front of it. There is also a fairly large black object reflected in it. A film crew perhaps?
After Life - S6-E3
Visible crew/equipment: When Dawn is possessed by the demon and breathes fire in the magic shop, in the bottom right corner of the screen in one of the shots, a metal tube can be seen blowing fire onto the set when it should be coming from Dawn's mouth. A hand can also be seen holding a blow torch, igniting the tube and then quickly pulling out of shot.
Visible crew/equipment: When Giles, Willow, Tara and Buffy (in Faith's body) arrive at the church in the armoured van, a camera is reflected in the van's back window.
End Of Days - S7-E21
Visible crew/equipment: Right at the end, when Angel saves Buffy from Caleb, the shadow of a boom mic can be seen in the top left corner of the screen as Angel helps Buffy to her feet and says, "I was never much for preachers."
Visible crew/equipment: The demons known as "The Gentlemen" always float about two inches off the ground. In one scene, two of them are moving through a park, and you can see the light blue cart they are standing on. (00:32:15)
Visible crew/equipment: When Dawn and the other girl are getting up after falling through the bathroom floor into the basement, you can see a man standing behind them towards the left side of the screen.
Out Of Mind, Out Of Sight - S1-E11
Visible crew/equipment: At the very end, as the invisible girl gets taken along a corridor by the FBI agents, check the top of the screen - a boom mike creeps in as the agent says his line, then is withdrawn.
Visible crew/equipment: When Willow and Tara are talking about Dawn, just as Willow turns around from hanging her picture to say "help?", a boom mike drops in from the top of the screen. (00:18:35)
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.
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.