suicide: always serious. it being humour makes it differently annoying. can't be having with it stil

I don't know about this one. If Xander really wanted Spike dead, he wouldn't have saved him later in the same episode. The show is known for using humor even about serious matters, like Anya trying to get Xander's friends to wish him dead, which was so twisted and wrong, but was played for humor.

Xander literally followed Cordelia into a shop repeatedly in order to insult and antagonise her.

Just rewatched Choices, Xander going into the shop was a follow up to Cordelia's earlier insult in the same episode. In Choices, Xander was telling his friends about his summer road trip, and then Cordelia just cut in not only to insult Xander, but also to throw digs at his friends. When Xander sees her at the shop, he literally says, "I have a theory. Your snide remarks earlier? I'm guessing grapes a little on the sour side. "

If Cordelia hadn't started the whole thing in the beginning of the episode, I don't think Xander would have walked into the shop for a pay back.

I'll give you The Prom, though. He clearly went in there to mock Cordelia.