Playing for fun versus advancement

One of the things that makes you want to always fight one more battle in World of Tanks is the advancement of your tanks and tech tree. The experience points you gain in each battle allow you to research better equipment for your tanks, or unlock tanks from a higher tier. But recently I noticed something unusual about my behavior in WoT: I stopped caring about advancement. I'm at tier 7 out of 8 in artillery, 8 out of 9 in both medium tanks and tank destroyers, and 9 out of 10 in heavy tanks. Bu

World of Warkraft...