Well, no matter what game you go to play on X-Box Live you are almost guarunteed to hear people talking and you yourself might talk as well. Almost 99% of the time you will find some typical people that are just flat out annoying.
First off you'll commonly find "that guy" that just tries way to hard to sound cool and impress people even though it's people he doesn't know. For example he'll either brag about how good he is at whatever game he's playing or he'll try and make his pathetic life sound better than it actually is by saying he has a hot girlfriend, plays football, and so on.
Also you're always going to hear that little kid with the high pitched voice, and along with the little kid they will be "that guy" who tells him to shut up till his balls drop. Just pointing out the obvious but it's a VIDEO GAME and there are bound to be little kids on it so deal with it.
Then sometimes there will be a girl playing who always lies about her age (much like everyone else) who also says shes hot and gives her myspace adress to all the fag guys trying to impress her. Well I'm sorry to say but unless you get lucky you won't find a hot girl you're age on X-Box.
Alongs with these people you'll also find the groups talking to each other, somebody who makes annoying sounds and sings, and maybe even the asshole playing music into his mic.
Don't lie but everyone's guilty and everyone who plays on X-Box Live knows what and who I'm talking about.