These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
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.
Hollywood 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.
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.