I don't think I've ever seen a fanbase that's totally perfect or totally insane. Yeah, I've been called out and insulted for daring to suggest something different to a particular fan's tastes, but from those same suggestions, a lot of fans have listened to me and tried new things.
For example, after I showed my younger brother Zero Punctuation, he's been on a hating spree of J-RPGs, bashing them with every justification Yahtzee used and maybe one of his own. His own argument is that the characters' eyes are too big. From there, it's an anime-hating spree, and he gets on my case for having the nerve to even LIKE Touhou. He also makes fun of me for being an artist, claiming that I do nothing but scribble all day to no avail.
So, from just that, I can draw that it's not only fanbases that are annoying; it's fanbase bashers. I'm willing to accept that a lot of people don't like Touhou, anime, or drawing, but it gets pretty darn stupid when they can't justify their dislikes and feverishly attempt to hide the flaws in their own preferences.
The most respectful fanbase I've been a part of is the Touhou fanbase, but then again, I probably haven't even seen the bad side. On the good side, we've got people who write doujins, build animations, draw fan art, and play the games, but know that the majority of our friends would prefer not to know about it.
