I would like to take a moment to talk about my experience with hunters, as a tank, in 15-80 instances. (note: I am aware that not all hunters behave like this)
I wasn't having problems with this until I got to the high-50's to low-80's, except a few huntards here and there. Soon enough almost every other instance I was going to, either DPS or healer thought it was a great idea to just solo the instance without me. Normally I just take the hint and start going faster. Now, note here that for MOST of them, they apologized if I didn't want them doing it, and I just let them do whatever they wanted to do because they were nice about it. This happened with paladins, mages, priests, and DK's. The only problems that I had were hunters.
Example: The other day when I was doing WOTLK dungeons, I just so happened to get a few very bad runs in a row, most of them with the same healer. This started with a particularly bad case. I was in The Nexus, getting aggro and killing mobs as I normally do, when I realize that the hunter has growl on. I politely tell him to turn it off and I get on with the instance. After a few pulls when he STILL has it on, and his pet is outaggroing me, I start to get a little impatient. I tell him to turn growl off, with no reply, growl still on, and his pet stealing all the aggro despite my attempts at getting threat. (I was a brewmaster monk, and even provoke wasn't working.) I had to say, "turn your fucking growl off, god damn" before anybody seemed to notice. Paladin replies, "lol why? his pet is a better tank than you anyway." Healer replies, "stop complaining, if you can't hold aggro then he has a right to tank for you." Hunter is still the silent douchebag in all of this. Eventually I say fuck it and stop trying to get threat. Then I get kicked.
Oh, and I just want to take the time to say that when the hunter was tanking, the instance was going MUCH slower, while when I tank and everybody does their job, everything goes smoothly and quickly.
That was probably the worst case, thought it certainly wasn't unique in the "hunter refusing to turn growl off and aggroing the whole instance with the healer behind all of his actions" area. What I'm trying to say is that, although hunters aren't the only class that pull, I haven't met a single hunter who isn't a complete asshole. Not ONE hunter I have had the pleasure of getting grouped with had the manners to not pull, even when it was his first time in the instance.
And you hunters wonder why you are always getting picked on.