I've found Halo extremely stressful (and as a result, cause violent behavior) due to the fact that you will repeatedly die in 1 cheap hit from someone whom you can't even see because they're hiding far away.
With rocket launchers, if the person using it aims properly you are guaranteed to die in just one or two hits, with sniper rifles you'll be getting killed by headshots every 5 seconds and if not you'll be mostly dead anyway...
It is this which gives violent games a bad name, not the violence itself. The violence merely causes people to be friggin stupid sometimes, apparently, claiming the games had tricked them into believeing they could outrun the law and such.