Buffy the Vampire Slayer changed television. Not only did it give the world one of the most nuanced female characters in the dark fantasy genre, but it also showed audiences what a bad friend looks like. Xander Harris is the worst. He may be a member of the Scooby Gang, but he's not the kind of person you want in your corner when the world is being swallowed into hell.
Xander isn't bad because he's powerless, or because he has awful fashion sense. He's the worst part of Buffy because he's childish, he can be creepy, and he only thinks about himself. Every other character on Buffy goes through several seasons of character development, with narratives riddled with misfortune, but Xander just becomes more disappointing as the series progresses.
If you're a huge fan of Xander, this doesn’t mean you have bad taste, or that you're watching the show wrong, but there are plenty of reasons why Xander Harris is the worst member of the Scoobies.