In my opinion, this is the most upsetting part of The Gift. It’s not the saddest part, but I think it’s the most upsetting. At the end of the day, Giles has to live with this. That’s a hard burden to bear, and I think it might have been one of the reasons for him wanting to leave California behind.
Definitely, and it strikes me as one of the most disturbing parts in Giles’s character arc, period. I have severely conflicted feelings about this moment, although I (partially) understand his motivations for doing what he does here.