I'm watching s3 at the moment and it bugs me seeing how cruel he is to Buffy in s2 and s3 concerning Angel. More than once he has implied it is her fault Jenny Calender died. Knowing that in s7 he will be making Buffy the bad guy when Anya starts killing again because Buffy thinks they have to kill her makes him seem very hypocritical.

Xander's real problem is he doesn't believe in himself which mean he constantly belittles himself and can't trust that he deserves a good thing. The thing with Anya was because he was afraid to turn out like his own parents he didn't have enough faith in himself to know how different he was from them. kinda sad really, cause he's only of my fave characters of like all time lol

his constant jealousy and prejudice against demons (especially two very hot and sexy vampires named spike & angel) was very annoying.

i htink it wa shorrible what he did to anya on there wedding day. she was so upset i felt really sorry for her.

I removed the 'leaving Anya at the alter' option because that was covered by 'the way he treated his girlfriends'

I agree it was very sad, I felt so sorry for her I just wanted to smack Xander. It was also annoying that he leaves after doing that. He should have stayed and taken responsibility and dealt with the angry guests and relatives.
In fact I should probably add 'never takes responsibility for his actions' as an option.

Hypocrisy, jealousy and prejudice. The jealousy one kind of faded after season 1 but it just turned into anti-vampire prejudice instead. The hypocrisy just annoys me because it could have been written as character development/him seeing what it was like when the shoe was on the other foot, but it came across as pure hypocrisy instead.