Perhaps you did something across the border of crazy.
Maybe you shared accounts or bought gold. Maybe you use your brother's account after he quit. Or perhaps you have never even paid for WoW and you are a piece of the internet which has become conscious and begun to interact with the world.
Me? My first account was not mine. A friend I met early at college showed me WoW and suggested that I play it. I was reluctant to start pouring money into a game that I might not like (I'm very cheap, so yes, $15 is POURING!). He offered to loan the account of a friend that wasn't playing anymore, but whose parents were still paying for the account. Only now that I'm writing this do I realize that I was basically stealing from his parents. Damn. Now I feel kinda bad.
The account was just to try it out. I looked at the classes and decided that a shaman or druid seemed most versatile. My friend was Horde, so no paladins. Eventually I picked a shaman. Trolls looked cool, so troll it was. The name was Klepsacovic on Magtheridon. I'd used it for years before then.
WoW was much more fun than expected, so I played and played. Eventually I forgot that the account was just to try it out. I was playing it as if it was mine, investing a lot of time. During this time I learned more about the friend of friend whose account I was using. It worried me, but I wasn't eager to get a new account and lose everything. I lost it anyway. Around 6 months after I started he got majorly busted for software piracy; not like downloading, but distributing of big-name stuff. He needed money, so he took back the account and sold it. That was the end of Klepsacovic, or was it?
I wrote a mini-history of events after this, but that can come another time. Short version: I bought my own copy, stuff happened, and now I'm a prot paladin.