For example, I once swore I would never play enhancement on my Shaman. I felt like a Shaman was supposed to be an elementalist first, a summoner of the elements, and a caster, and that if I really wanted to just swing around dual wielded weapons all day, I had a Warrior I could go to. But recently I started a Shaman on a server other than my normal to check out the RP scene there, and I decided to try enhancement out for a bit.
I was suddenly hooked by the idea and the play style itself, enough that I went and respecced my higher level Shaman on my main server. I still play mostly as Elemental and Restoration when I play my Shaman, but I have gained a healthy respect for a pair of whirling weapons and the rather badass summoning of Spirit Wolves and all that.
Similarly, When I play battlegrounds, I try to never give in to the zerg. I try to organize who I can, and I'm never afraid to play a supporting role. I'll stay back on defense, heal, or play decoy. Whatever needs to be done for us to score and win, I'll do, even if it means I die constantly or get fewer Honorable Kills because of it.
However, with the recent School of Hard Knocks achievement, I have found myself on the forefront of the said mindless Zerg. While I'm generally at the site of multiple flag caps and returns every day, It's not generally me who's doing the capping because I'm busy making sure the Horde don't harass the flag capper. Unfortunately, that doesn't work for this achievement, so last night, I found myself out in front of the Zerg, ready to live the reality of Every Man For Himself.
So what about you? What nevers -- things you'll never do, classes you'll never play, places you'll never visit, and so on -- do you have when it comes to World of Warcraft? Is this never because of time, or skill, or personal preference? On the other hand, was there something you thought you'd never do that you've done?