As with similar simulation games, I feel it's a combination of your in-game abilities to become whatever one wants, to live out one's personal fantasies, and in short to control one's "life." That latter sense is what really can make players potentially disconnected from reality.
The 3DS launch selection was terrible, so I chose The Sims 3 as my launch game. Unfortunately it got pretty bad reviews which scared me out of playing it. Then two weeks ago I decided to play it, and I found it's surprisingly good. I played it for two hours everyday until I picked up Zelda, now I only play that.
I'm partly addicted to sims 3 for pc. If I play it, then the entire day ends up out of the window because I was either building houses or building community lots because i have afew ep's.
It's only addictive for a few days at a time. For me anyway.
I played it for a full week with no cheats for the first time ever not too long ago and already had everything I ever wanted to get in it. Riches, good house, all happy. There's not much else to do after that. And, controlling characters in a big house gets kind of annoying....