Favorite thing? That the game encourages you not to play. After all, you continue to accrue your skills while you are offline, which I thought was silly. Heck, you can barely improve the speed in which you accrue skills as well.
I don't know, I found the game incredibly...boring when playing it. There's not really much to do, and the scope is quite limited. It may be fun to others... but I found most of the things to do an incredible chore.