Even the most stalwart class-monogamist among us is tempted from time to time to take a peek at the forbidden fruit of another profession. That class selection screen, it is a cruel joke played upon our sensibilities! What should I pick? How do I know I'll like it 500 hours from now? It's like trying to choose a lifelong mate by only reading his or her personals ad. You need a bit more to go on.
Where was I? Ah, yes. So while we often give in to our altoholic nature -- or at least flirt with it by rolling up a new class just to see what it feels like -- sometimes there's just a class that is so repulsive that we can't ever imagine playing it. Maybe it's a role, like a healer or a tank or a stealth-based DPSer, that you've disliked in the past and are not inclined to experiment with now. Perhaps you don't want to be one of the crowd when it comes to uber-popular classes. Or maybe it's just a profession that offends your sensibilities as a connoisseur of fine gameplay.
So what class will you never, ever play in your game?