I really enjoyed this! I'm not a big Xander-fan, but I do like him in S7, when he has grown up a bit. I loved the style of this, with the parentheses and the way you didn't reveal the narrator. The character voice felt spot on, once I figured out who it was and the last line was perfect.

(He remembers laughing when he first found out; feels ashamed now that he was so flippant, for more reasons than one)

That was when I knew who it was, before that I was all over the place with my predictions. But that might've been me being a bit slow, IDK. :)