Why do you play World of Warcraft?

I'm curious as to why others play the game?

About to give it another play but my goal this time is going to be different then before. I want to simply see how the rest of the story plays out. That wasn't my original goal before as I was simply playing to interact with other players but that doesn't always seem to work out. So this time after playing Warcraft 3 again I want to see more of the rest of the story. It's the strongest desire in regards to the game now. So I'm starting fresh with a new character (human but haven't decided on a class but leaning toward Paladin). I have both the original game and the Burning Crusade expansion. So I'm going to see how far I can get before Aion comes out and I might actually split my MMO time between those two games for a while. I'll be focusing on the story in the game as well at the start too.

So why do you play or continue to play the game? Story, friends, pvp, addiction, etc?