I don't get addicted to games, and I don't get the appeal of having a higher level. I detest the very market structure of the MMO market, despite the past glorification and future dreams that massively online worlds would bring when we were but young 'uns looking forward with bright eyes to the future where we'd be glorious knights with our friends in a living world, that dream has been royally bent over the table by corporate titans setting the bar with a business model that solely advocates a massive time investment alongside small but plentiful rewards in return for the users loyalty. To me, MMOs aren't much different from the Facebook esque social casual games, except that MMOs are worse. They demand much more time and much more money for the same reward: The illusion of progress.
The flaw I find is in the subscription plans MMOs use, since you are paying as long as you are playing, the only thing publishers want is for you to keep hooked and dishing out the cash. If it were a one off payment, the game would have to be of a high quality since it has to have a good enough name to warrant you paying the initial price for the whole shabam.
But yeah, there have been very few small time MMOs I can safely say I've enjoyed. Ultima Online in the veeeeeeery early days, Face of Mankind, Haven and Hearth, and a few super old social based virtual worlds like Palace and Cybertown.
I think that games like Shores of Hazeron invoke true innovation and inspire me the most. That is the kind of thing I dreamt when I was young, sitting infront of my faux pas wood computer playing Ultima.