Its just like MySpace drama.... people get caught up in everything and feel the need to quit to take some time away. Either that or they are just looking for "Oh no, don't quit!" posts, which I wouldn't put past many users here.
I think that if people have been too addicted to AG, it is good to take some time off, go have some friends, etc. Also, I think people start spamming and the like, then realize they are in the wrong, and think quitting is their only option.