I find playing through the undead starting campaign to be pretty jarring, because basically there's so many points where I disagree with my character's forced choices. Lets face it, hanging around under the command of Sylvanas and Garrosh is awful compared with the treatment that death knights get in the alliance.
I find the same thing with the goblin campaign - seriously, why the heck do I stay under Gallywix after I thrash him? I just cannot fathom why the story ends with me going "Oh well, guess I'd better let that guy who stole all my money and tried to enslave me go, so he can go on to lead my faction instead of me."
Seriously, both of these starting campaigns make me feel like my character is some sort of grade-a idiot, not a budding hero.