The obsession to have alternating caps unnecessarily in a gamertag, as well as 'ii' xXx Oxv vxO' either sides, etc.
or the opposite... people that CANT level and are stuck at low level ruining the game for others. I won 100+ games in a row in doubles and im a lvl 30 =.=
Mine are racists... Some people have racist gamertags and screenshots, and others are just pointlessly racist to many people.
people that say things didn't happen. i.e. "That Laser didn't hit me, but I still died!" Obviously the laser hit you, because you died.
Stupid annoying little children. This covers most of what other people said: -mlg sayings -obsessed with rank -trash talk in a high pitched voice -think they are cool and legit -generally all around obnoxious