Basically, just say what annoys you the most about MMA fans, even better if we're discussing educated ones who know that Chuck Liddell isn't fighting anymore and the like.
For example, the most annoying thing about MMA fans for me is this elitism that if you don't find certain aspects of a fight exciting/a certain fighter exciting, you "must not be an MMA fan". Come on, you can find a BJJ match fun, a sloppy brawl, a highly technical kickboxing match awesome, but stop telling other people what they can and can't like.
Personally, as long as a match is relatively high paced or one of the fighters is doing effective damage or grappling, I'm happy and can watch a match and enjoy it, it's when there's stalling against the cage with little strikes that I can't stand. Worse than lay n pray in my opinion. I also do not find Frankie Edgar that exciting beside when he's receiving his monthly concussion, which leads idiots to tell me "you aren't an MMA fan, he's so brilliant!"
Yes, he is brilliant, he's a fantastic fighter. Well so is Jon Fitch, and many people find him boring. Frankie for me is a low power puncher, who's punches do not often hurt opponents severely and do not have much chance of knocking opponents out. I am not one of these fans who needs a knockout to be entertained, but I'd rather watch fighters punch each other and look like they could end the fight rather than Frankie land a million shots that don't do much (Maynard rematch aside, I was impressed he got the KO there)
So what do you find annoying about MMA fans ? The fickle nature ? The non stop hate of fighters who don't really deserve it (like Rashad) ?