One of my very first toons was a fire/mace tank. I was kicked off of a team for not having taken Taunt yet, despite not being a high enough level to take it. After some time soloing and finally getting on another team, totally different people, I got to the level where I could take Taunt, but at that point I could also take Consume. I knew that I could not keep my toggles going, and if I couldnt do so I could not stay alive, so I took Consume instead, and got kicked immediately after the team leader realized what I had done. This turned me off of tanks completely, and it was years before I tried again (and found that I loved them).
Other than this one lousy experience, I do not remember other times where that sort of thing happened. I know people questioned my build choices, but I cant remember any time where they were talking to me as if I was doing it wrong, only curiosity or trying to provide advice.
I avoided the "optimal builds" because to this day I dont think CoH had them. I think some powers were better in some situations, but nothing was ever necessary. I have played the only melee toon in an ITF as an electric/electric brute with no taunt and we smoked it. I've done all /thermal controller ITFs and STFs and had a ton of fun. I knew people with the standard fire/psionic permadom build, and made an electric/psionic to be my own farmer (slightly slower, far more survivable), had a friend do plant/psionic permadom as another farmer, and another friend do mental/psionic permadom just for giggles.
Other games have the "right" way to play, the optimal gear, combination of classes, whatever. CoH never fit into that for me. Maybe I was just with the right people, or the wrong ones if we were doing things so poorly, who knows.