This episode marks the only time Buffy's birthday is celebrated on the show in which the inevitable unfortunate event doesn't happen to her, although to someone close to her.
Maggie Walsh questions Buffy how many "hostiles" she has killed; it's known she has killed more than a total of 100 demons and vampires.
Douglas Petrie has mentioned the creative process for this episode's metaphor:
"Well, we felt that Giles was a little bit underserved at this point in the season and wanted to give him something to be doing. It's always fun to have Ethan Rayne back in the mix. Really, this is Giles' mid-life crisis episode. It was the first time that we got to deal with a metaphor that was that adult, not teen-orientated at all, and quite a bit of fun. [...] There were a couple of ideas kicked around. We were talking about a portal. We were talking about him becoming younger, him becoming older, him kind of recapturing his youth by becoming - I don't think seriously - but I know Jane Espenson was kicking around the idea of getting teenage actors to play teenage versions of Giles and Ethan and to have young Ethan try to seduce Buffy. That was an intriguing idea but ultimately we went with a pretty straight-on metaphor of his questioning himself in the middle of his life and he's turning into a monster."
A line of Spike wasn't aired in the final cut of episode. It's after he smashed into the building with Giles's car: "I can kill demons. I can crash cars... Things are looking up!"
This line from Buffy was cut from the script: "I'm so sorry about, you know, stabbing you in the heart."