I always find that, when it comes to The Sims, I always play the first iteration a lot, then a bit of the first expansion, then as they add more little "mini-games" I just lose interest. I think the reason why is because I am horribly controlling of my Sims and how they act, and as each "mini-game" comes out adding the ability to go out to clubs, or visit china, or become a ghostbuster, or become a celebrity, I just lose interest because I don't see "my" Sim doing most of those things, and if I do make them do it, I feel I made him a bit to "perfect". I would go to another household but, then that goes back to the controlling issue, as my main sim is now off doing who knows what.
If I decide to play again I might try really hard to do a generational neighborhood where I actually let my Sims have kids, die, and then make the kids do some of the things I wouldn't do.
Well... when I can actually play anyways. Still need a new computer.