I have a confession: I was once a tank. Technically I could have been half a tank, because I think I healed just as often, but once upon a time I rolled a druid with the intent of getting a melee DPS perspective.
One night in Wrath of the Lich King, my first guild had some trouble with kiting the adds on Gluth. So we upped the tank count to 3: the paladin tank moved to the back for holy tag with the undead while the former-bear warrior walked me through my feral spellbook as I sat in bear form on that pipe. I think it was the extra Mauls that hooked me. I became a bear tank with a branch-waving offspec.
I have fond memories of alt or PUG raids where I had cooldown-busting health pools and hero-bear resurrections between Gormok's death and the arena entrance of Acidmaw and Dreadscale. But as my guild tore apart in the beginnings of Icecrown Citadel, I've been back to pewpewing from the back as a warlock. My bear is merely an alt.
But my bear has made my warlock a little stronger.