1. “G2G My mom needs to check her email…” child
This one will generally wait until you’re deep within an instance  before speaking(If you’re lucky). After an hour or two of fighting just  to reach the final boss…he has to go. Mommy is kicking him off his  computer. While I have no problem with children playing MMORPGs(except  the Lawl, phat lewtz noob I pwn your azz morons), these types of  situations are some of the most annoying.
2. The Beggar
Picture this. You’re just minding your own business in Ironforge when  suddenly a trade window pops open. While confusion sets in for this  random trade exchange, you’re suddenly bombarded with tells from the  assailant to give him money. S/he always has a variety of reasons of why  you should(Abilities, Mount, No reason, etc) however they get UPSET at  you for asking why they need it. After denying them your hard earned  cash, they generally leave you with a few “choice” words.
3. Guild “Looter”
Every guild has seen a swarm of these, especially those trying to  make a name for themselves. These are the people that join your guild,  get the best gear you can offer them, then leave to join a guild higher  up than your own. Constant “attacks” by these people are generally what  make small/medium sized guilds practically stop trying. Or give up hope  for humanity.
4. The Girl
I’ve seen one of these in every guild I’ve played in. You’ll  recognize “The Girl” right off the bat. She’s the one that constantly  throws out sexual innuendos, talks about her MySpace pics, and gives out  links to “her” guildies of her posing naked or various other  “activities”. Please note this is not a statement against all gamers  that are “Ladies”. Grow up, kid.
5. The Alt Looter
As a Rogue and a Hunter, I’m pretty much constantly competing with  other rogues, hunters, shamans, feral druids, fury warriors, etc for  gear. I’m fine with that, it’s fair. This brings me to the “Alt Looter”.  This is the person that, for example, will roll on DPS loot while they  are Healing spec’ed. Getting alt gear sets when the item will  potentially rot is fine, but taking loot from classes that need it now  is just greedy.
6. The Know it All
Never question this person’s authority on any topic regarding the  game you are currently playing. The “Know it All” is the person that  hoards all knowledge and will quickly jump down upon anyone that says  something that isn’t correct. Do they do it politely? Of course not. It  generally involves calling the one at “fault” retarded, a newb, and  other colorful words. I could go on..but I’m filled with rage.
7. Wife Aggro
When you start referring to your spouse as a faction, and the fact  you’re still playing an online game is causing you to “gain aggro”,  you’ve entered into a scary place. Or a funny one. However you cause  your group nothing but grief when you leave claiming you have to gain  points or you’ll not get food made for you anymore.