I know what you mean... I was thoroughly shocked as well. I have never really run into anyone too obnoxious in MK. I play CoD a lot... and as you probably know there are a lot of annoying children who clearly had horrible parents so the act out... but Injustice is just... yeah... the worst in terms of player base. Seems like I cant get into a KOTH without annoying people. The game is OK at best. I still love it... but to be honest it is kind of more of the same. It wouldn't hurt to put it off until the games price drops a little.
