Or maybe some people are so intent on seeing the good that they don't completely see the bad. Xander feels some remorse AFTER HE'S CAUGHT cheating on Cordelia, for about an episode, but even then, what does he do? He justifies his actions. He does something similar with Anya. He never takes on COMPLETE BLAME or COMPLETE GUILT, even though HE'S THE ONE COMPLETELY AT FAULT. And not to mention his hand in the Angel thing, in which, not only does he not show guilt or remorse, but actually seems to relish the idea that Buffy might've had to kill Angel. He doesn't think at all about the pain that would cause her. He actually attempts to make it happen again! What a good friend.