Deleted Scene: In the original script, there is an entire scene of Angelus bantering with Jenny's uncle which was cut. The actors credited as "Teacher" and "Student" do not actually appear in the episode. The scene they were appeared, which revolved around Buffy running out of class after a series of dark thoughts about having sex the night before, was cut due to time.
I don't think it's the "forged" that's the important part—it's more like "no weapon YET forged can kill him." That's why Buffy says "that was then—this is now." Times have changed.
Hilarious in Hindsight: Spike taunting Angel about how his love for Buffy turned him into her lapdog. Spike eventually falls for Buffy himself, only to end up the "whipping boy" for all her unresolved Angel angst.
Idealized Sex: In Buffy's dream, showing how she has idealised their relationship.
Idiot Plot: More than a few fans and critics have questioned why gypsies would create a spell with a "perfect happiness" loophole. But it's never said that they did this deliberately, it could simply be the way magic works. When you've got spells lasting for eternity or that affect people over generations, the Universe or the Powers That Be would need a safety valve or the whole world would be full of cursed people. Alternatively, you could take it as the Kalderash being so obsessed with vengance that, instead of allowing the cursed Angel to have any respite from his torment, they considered it better to end the curse if he did achieve happiness than allow him to continue living with some form of comfort.
The Other Darrin: In the flashback scenes of Buffy and Angel making love, the heavy breathing wasn't voiced by David and Sarah, but rather by series creator Joss Whedon and supervising sound editor Cindy Rabideau. (Apparently Joss was too embarrassed to ask the stars to record it.)
Rewatch Bonus: Uncle Enyos belief that the return of Angelus was 'arranged' is a lot more plausible knowing he's a tool of the Powers That Be, both good and evil, in the spin-off series, and Twilight in the comic series.
Signature Scene: For a lot of fans three things come to mind with Buffy: her macking with Angel, her being a Bastard Girlfriend to Spike, and her shooting a rocket launcher at her vampire ex.
Throw It In: The scene where Angel dumps Buffy in his apartment was not supposed to take place there. Halfway through shooting the scene on Buffy's lawn, Sarah Michelle Gellar and David Boreanaz told Joss that the scene wasn't working, so he moved it to the bedroom. Buffy is still heard saying she saw him at "the house".