And of course that's the sort of game some addicts continue to play well past the point of just beating the campaign -- Diablo 2 servers are still running. Grinding for great loot and maximizing their character as much as possible compels some people to play these sort of games for years on end.
This is precisely what I learned about MMORPG's after playing my first two. For one, in these games, you're never "there" forever. You always have to play catch-up with whatever updates that are implemented.
You ever read this article?http://www.cracked.com/article_18461_5-creepy-ways-video-games-are-trying-to-get-you-addicted.html
I had to quit FF11 and decided to not get back into MMORPG's for a long time. The addictive qualities I noted:
1) You can feel a sense of achievement every day.
2) The world felt like a secondary home, or perhaps a home you wish were your primary home.
3) The ridiculous amount of time spent accomplishing stuff makes you think, "well, I've invested this much time, why not invest more?"
4) The ridiculous amount of things you learn make you feel like you are fluent in an advanced skill, so it's fun to keep perfecting this skill.
#1 is possibly the most important factor, and it is noted in the cracked article. The problem with real life is that you typically can't get anywhere just by working hard. Maybe some people can, but those people aren't going to be addicted to MMORPG's. Working more hours at my job won't really achieve any goal and school predetermines when I finish. Neither are particularly enjoyable, as well. An MMORPG that is enjoyable and gives you the ability to get "there" as quick as you can spend the time to get there is a recipe for addiction.
It's almost horrifying to realize the feeling of subconscious fulfillment when playing FF11 vs. not playing FF11. The feeling of achievement is what keeps me from feeling empty inside, and FF11 sure helped, basically every day I was able to play it.