I also have a very ambivalent relationship with online shooters. I enjoy playing them alot, but the immense immaturity, trash talk and unsportsmanship that I often encounter can be overwhelming. So much that sometimes after an "intense" session I "give up" and don't play them anymore for months.
I think that I'm a very good player -I've been playing shooters since Wolfenstein 3D- and that can be a problem. I play WarRock alot - its free - but you can buy premium accounts and spend ingame money to buy bigger weapons than the standard-issue rifle.
I lost count of how often I've been kicked from a game because some idiot can't believe that I keep killing him even though I'm using the standard rifle whereas he is using the 30.000$ FAMAS. I receive alot of verbal abuse for being good almost every other game and get kicked about one third of the time.
On the other hand, I can understand why people are so wary. Almost every game I'm in has someone using hacks. With WarRock there's always "waves" of hacker infestation. Sometimes after a patch its all good for a while, but sooner or later it starts getting worse again. I completely don't get the cheater mentality. I don't see the fun in pointlessly gunning everyone down without a challenge and ruining the game for everyone else.
Then there's the standard verbal abuse of course... I try to ignore it as much as possible.
I wish there was a good shooter with some kind of age-authentification. Over 25 year-olds only. I'd totally go for that.