I've been a reading a lot of stories about how when Giles and Joyce get into a relationship Buffy is super thrilled and understanding. Any initially angsty/non-happy or maybe just creeped out Buffy in the same situation?

The Uncontrollable Series by Sweetprincipale on fanfiction.net. Plus the Sex and Candy Series by the same author. Buffy isn't exactly happy about the relationship at first but she comes around eventually.