Band Candy - S3-E6
Trivia: The accent that Giles uses as his teenage self is Anthony Head's natural accent.
The Freshman - S4-E1
Trivia: At the Bronze, Buffy sees someone whom she thinks is Angel. Until his face becomes visible, revealing it's someone else, the man she sees is played by David Boreanaz.
Once More, With Feeling - S6-E7
Trivia: In 'Once More, With Feeling' the man singing the mustard song is David Fury, the co-executive producer.
Trivia: In the final episode when Buffy, Xander, and Willow are wandering off talking about shopping, Giles turns round and says "The Earth is definitely doomed!" This is a little tribute to the end of the episode 'The Harvest' when Buffy, Xander and Willow wander off talking nonsense and Giles turns round and says a similar thing.
Once More, With Feeling - S6-E7
Trivia: In 'Once More, With Feeling' the woman singing about her parking ticket is played by Marti Noxon, the executive producer.
Once More, With Feeling - S6-E7
Trivia: In addition to singing "Rest in Peace," James Marsters also played the song's guitar track.
Trivia: There have been several lines throughout the series have referred to Tuesday ('There's a demon trying to destroy the world and it's just another Tuesday night in Sunnydale' in Revelations and 'Dawn's in trouble. Must be Tuesday' in Once More With Feeling). These are references to the fact that, in the USA, Buffy is aired on a Tuesday.
Tabula Rasa - S6-E8
Trivia: In the episode 'Tabula Rasa', Buffy says to Spike 'A vampire with a soul? How lame is that?', a dig at spin-off show 'Angel'.
Trivia: The actor who plays Nicholas Brendan's evil twin in "The Replacement" is actually his real life twin, Kelly Donovan. Both the brothers use their middle names when working rather than their real surname, Schultz.
End Of Days - S7-E21
Trivia: This is the only episode to feature the lead actors from all four of Joss Whedon's Mutant Enemy productions: Sarah Michelle Gellar (obviously), David Boreanaz guest starred as Angel, Nathan Fillion (from "Firefly") played Caleb, while Eliza Dushku, who played Faith, was the lead on "Dollhouse".
Trivia: The 'Grrr Arrrg' monster at the end of each episode (ie. the mascot for Mutant Enemy Inc.) is something that alot of people watch through the credits to see. But if you watch at the end of 'Becoming', he walks past and says 'Boo hoo, I need a hug'...and at the end of 'Once More With Feeling' he sings his 'Grrr Arrrg'...and in the Episode 'Bargaining Pt. 1' Tara gives Giles a small monster as a goodbye present, 'Something to remind you of Sunnydale...' and then goes 'Grrr Arrrg'....Ain't little monster's grand. Also at the end of the Christmas episode where Angel tries to kill himself, the monster is wearing a santa hat, and, at the end of the graduation episode, the monster is wearing a mortar board.
Trivia: In the Buffy episode 'Anne' we are re-introduced to a character played by Julia Lee. Called Lily in this episode, she was previously called Chanterell in the season 2 ep 'Lie To Me'. At the end of the episode, Lily asks Buffy if she can be 'Anne', Buffy's L.A. persona, to which Buffy replies yes. It is interesting to note that Julia Lee returns later in several season 2 'Angel' episodes as Anne, though by now she has grown up significantly and is now running a hostel for runaway youth, something she once was...
Trivia: Buffy's chums are regularly referred to as 'The Scooby Gang' which is funny, because Sarah Michelle Gellar actually went on to become an original Scooby as Daphne in Scooby-Doo, the movie.
Trivia: Many elements of Xander's dream in 'Restless', season 4, were seen again in the season 6 episode 'Tabula Rasa'. In the dream, Spike wears a tweed suit and tells Xander he's in training to be a Watcher (Giles adds "Spike's like a son to me."), also mentioning 'A shark, but on land. A land shark'. In 'Tabula Rasa' Spike is under threat from a loan shark (literally a shark), disguises himself in a tweed suit and after a spell gone wrong believes he might be Giles' son.
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.