You want to stop Bastion? Grab a D'Va or two. Her projectile shield will stop his machine gun AND tank shots completely. She also has a decent machine gun that never reloads and her ult essentially wins games. You just drop your current mech on the enemy team, boom, triple kill.
I find myself maining her even if I'm not the biggest fan of her personality. Hell, I find myself playing mostly the tanks. Only one I can't really get into is Zarah.
Currently I play Lucio, D'va, Reinhardt, Roadhog, and occasionally I'll play as Mcree or Widowmaker to help the team, but I'm a pretty poor shot so I don't tend to do well as them.
North888#1455 if anyone wants to add me on Battle.net, and Clide444 if anyone wants to play on PS4, though I'll probably only pick up the PC version when it comes out fully.
As far as the things that infuriate me...Hanzo...Just...everything about Hanzo. Junkrat can get annoying and Widowmaker can make me very angry at times. Mei is also severely annoying at the tail end of a game when on the defender team cause her Ice Wall can just hold you up for those precious seconds, and her freezing, if done well, can completely destroy teams, especially her ult.