Oooooookay. After reading through all the pages so far (and scrolling VERY quickly over the posts of a certain jackass who put a Weeping Angel in his/her sig), I've decided to throw my two cents into the charity box, if you will. (My "points" will be numbered, so reply to whichever one strikes your fancy)
1.) When it comes to anime fanbases, it doesn't matter what anime it is, the shippers are always the worst. Ones that stand out for me are the Naruto and Bleach shippers. I swear before Arceus, Celestia, and Zordon, I truly have lost count of how many times I've seen "SASUxNARU 4EVER!!!" or "ORIHIME'S A **** ICHIGOxRUKIA 4 LIFE!!!1!11!!!!!" on the various forums, discussion sites, and image boards I visit. It takes every ounce of my power not to personally tell every last one of these morons to GET A GODDAMN LIFE. I do not follow Hetalia, but from what I've heard, the shippers in that fanbase are even WORSE. *Sigh*
2.) As a loud and proud Brony, I can say with confidence that not all of us here in the Herd are "cloppers", despite what the always-controversial Howard Stern would like you to believe. Most of us are just regular guys and gals who happen to enjoy Love and Tolerance. On a side note, we also have our fair share of shippers (I for one am a rather proud ApplePie ((That is, ApplejackxPinkie Pie)) fan), but unlike other fanbases, we do our best to be calm and respectful about it, instead of shoving our desired pairing down everyone else's throats.
3.) One of the worst types of fans out there, that I've come across, is the Nostalgia-F@gs. That is, people who see a new game or show or booster pack coming out and immediately begin outcrying "THEY RUINED IT OMG ORIGINAL SERIES 4EVER ONLY!!!1!!!11!!!!!" Whether it's Pokemon, Sonic the Hedgehog, MegaMan, Devil May Cry, Resident Evil, or any other show/game/what-*EFF*king-ever, these retards are bound to rear their ugly heads and spout their nonsense to anyone and everyone who can see it, while at the same time refusing to listen to reason and only yell the same sh*t only LOUDER to drown out those who attempt to argue with them. To any and all Nostalgia-F@gs who are reading this, consider the following advice: Stop f@pping to Sailor Moon, move out of your parent's basement, and LIVE IN THE MOTHER*EFF*KING NOW!!! Accept the changes and get over yourself, for Christ's sake!
4.) I don't get involved with many video game fandoms (sans Pokemon, but that's a whole different story) but thanks to my recent addiction to Skyrim, I've become rather aquainted with the fandom, and boy oh boy, do they have problems. Most of them are respectable enough (so long as you dont disrupt them during a dragon encounter), but if you want to see flame warring at it's finest, go to any Skyrim forum and bring up the crème de la crème of flame bait topics: the Civil War questline. Almost immediately, you will get the community divided into three sections: The Imperialists, The Stormcloaks, and The Treaty-Lovers. It would take far too long to break down their psychie, so I'll just let their rallying cries do the talking. Imperialists: "4 ZE EMPURUR!!!" (I wish I was kidding). Stormcloaks: "NORDS ONLY! TALOS 4EVER!!!". Treaty-Lovers: "Stop the violence! Work together!" (Notice how I didn't put their rallying cry in all caps? That's to symbolize how much more sane they are compared to the other 2 factions, and thus more likely to go unheard). It may seem impossible to get them to quiet down once the topic's been presented, but there is a way: Bring up the Thalmor. For a brief few pages, the community will be unified under the common goal of slaughtering those Nazi-wannabes, but sooner or later, someone's gonna bring up the topic of either who gets the glory for destroying them or what to do afterwards, then the whole thing starts ALL OVER AGAIN. Sad, isn't it?