I quit WoW, rather I'm taking a break from it, because I simply just don't have time.
When I played WoW it was right after SPM when I didn't have a job etc, I spent literally half of each day playing it.
Now that I'm in college and I have so many other games to play, I don't see the point in playing WoW at this time. Something will give: either that's the only game I play, my grades go lower, or I make no progress at all by only getting to play like 1 or 2 hours a week.

Eventually if I have a long break or something I'll pick it up again, I have a level 37 mage which I really want to get to 85. I think once it gets there I can happily quit without looking back. But either way when I do play it I have a great time, so until then permanently quitting would be pretty sad