I really, really hate the Xander/Anya relationship in Buffy. I'm re-watching seasons 3+4 this week and her sudden appearance in his life makes zero sense. She was there to grant a vengeance wish for Cordy after he cheated on her, suddenly she's human and wants to go to PROM with him???
They tried so hard to fit Emma Caulfield into the ensemble and replace Charisma Carpenter but it failed on all levels. Plus, she's so creepy in early season 4 when she strips off for him (he looks genuinely scared) and she's rude to everyone, particularly Giles.
Sorry for the rant (actually I'm not)