Big Bear Butt Blogger is a feral Druid who asks the all important question: why be a tank? His answer is "because it is a heck of a lot of fun tearing your way through everything in front of you" as shown in the clip above that he provided.
I think this is also a larger question to you die hard tanks out there. Why do you tank? Is it the thrill of being on the front lines? Is it the command of the situation? Or do you like to smash things?
I'm not a big fan of tanking myself. I've done it enough on my feral Druid to know that it's too claustrophobic and too easy to mess up for my tastes. I prefer to stand back and heal to see the big picture or cat dps while keeping an eye on everyone else to make sure I don't have to shift to another form to help an over-aggro'ing Mage or a Hunter pet that's going down.
What is your motivation behind playing a tank?