When I first started playing with it, my parent's didn't allow it because at the time, they thought all online games were evil so I had to play it on the sly; when they were not home or when they were safely preoccupied. I guess that was when I was really addicted to it and devoted all my 'available' time to it. Now, since my parents are cool with it, it's become no more than say CS when I was into it and I can easily go without it.
Still, one of the hugest flaws with WoW is that many in-game dungeons and raids can easily take hours up of your time: you have to first get a group together, then you have to actually get there which, at times, can be a real hassle, then the dungeon itself can easily take up to 30 mins to an hour, and then afterward, you usually feel compelled to either deposit our sell some of the items that you got. This is all if it goes off without any hitches, such as somebody has to leave early and you have to find someone to replace or something like that. And something as simple as doing a dungeon can easily take up to 2 hours to complete.