How To Be A Good Anti-Fan
I was an anti-fan of both Eragon and Twilight due to my dislike of both franchises. In both cases, it was fun at first - I would discuss their flaws and groan over the particularly bad parts other like-minded people. But then, something would happen - the anti-fans would gradually stop presenting thoughtful and well thought-out reasons for not liking them, and in time began acting more like a bunch of rioting poo-flinging chimpanzees. They were easily just as bad, if not worse, than the fans they had thought themselves so superior to.
So, here's a guide on how to prevent yourself from going down this dark path.
Unless you can elaborate on why you don't like it or one or more characters, keep your mouth shut.
Seriously. If all you can say is "X is horrible" or "I hate X!" shut up and go away because you're not contributing anything useful. Instead, you should write out logical, reasonable, and informative statements like "I think X is terrible because Y is the most ridiculous thing I've ever seen" or "I absolutely hate this story because the plot just wouldn't work if the main characters had any sense at all," or "I cannot stand the story because the main characters act like horrible people, even though we're supposed to be rooting for them."
If you can't express how much you hate it or the characters without resorting to slurs or attacks on the characters' sexuality, keep your mouth shut.
You are not contributing anything useful in the slightest. It's quite all right to say "I don't like Edward Cullen because he's a borderline-abusive control freak" or "I can't stand the Meyerpires because sparkling vampires are ridiculous!", but not only is it not okay to degrade the characters or work with slurs, it's morally and ethically wrong because you are fostering hate toward the group the slur usually applies to. (And no, "I didn't mean it that way!" is not an excuse. If you still want to insist it is, please read Intent! It's F------ Magic! At least, if you're not offended by strong language.)
Don't judge the work based on the behavior of certain fans.
The behavior of the fans has no bearing on the quality of the work itself - and guess what? Everything has absolutely horrible and disgusting fans, including the things you love.
Check your double-standards.
I've seen fans of Harry Potter share stories of how they had done things like harass Twilight fans in bookstores or had shouted over the movie in theaters - the selfsame fans who are convinced that Harry Potter fans are so much more mature and intelligent than Twilight fans. If any Twilight fan had done this to them, they would have been holding it up as evidence of how horrible and rude Twilight fans are. Essentially, if it wouldn't be okay for a fan of the thing you hate to do it to you, don't do it to them.
Do not insult people simply for being fans.
Seriously. If you see someone quietly reading a book you hate, leave xir alone. If someone merely tells you that xe likes something, don't insult them in any way, shape, or form.
Mythology changes. Deal with it.
All of you who complained that vampires aren't "supposed" to sparkle, I'm looking at you. You don't have to like sparkling vampires, and you have every right to go around telling the world how ridiculous you think sparkling vampires are, but there has never been a time when vampire mythology wasn't being changed and fiddled with. Same goes for pretty much every mythological/folkloric creature you can think of. I reiterate: you do not have to like the changes and you can tell the whole world how bad you think they are, but whining about how something is or isn't "supposed" to do something is naive and useless.