Simplicity is the ultimate sophistication.
The world of the MMORPG is a time consuming one. The longer you play them the more rewarding the experience becomes, and the day to day routine of carrying out repetitive tasks, such as visiting the auction house, crafting items or fighting a few beasts in order to gain more EXP becomes an addictive experience and one that's hard to put down. The fantasy setting of any MMO allows you to escape from reality for a few hours and immerse yourself totally in a new world as you join up with like-minded people and form friendships, discuss how to tackle a particularly tricky quest, advise each other on how to craft certain items or bond together as a group to share the adventure.
As I write this, hundreds of Hobbits, Elves, Dwarves and Men are wandering around a virtual Middle Earth, forming fellowships, farming in the fields of The Shires, searching for silver ore in the misty mountains, fighting Goblin prowlers and embarking on a myriad of intriguing quests in an attempt to drive back the evil forces of Sauron. In almost every way, Lord of The Rings Online: Shadows of Angmar is typical of any highly addictive massively multiplayer role-playing game.