I went as far as downloading the ultimate S2 collection the other day. That's how bored I am. But the graphics... urgh. And the thought of collecting x number of mods to make it tolerable just exhausts me. Besides, to my knowledge, there's no sex mods like Kinky World or Whicked Whims for S2 so - even less incentives.
In any case, I usually build something specifically for one sim/family - with a story in mind to be played out. Then I playtest the functionality of the house - then I quickly get bored of the shallow gameplay with sims who have no personality - then I start the cycle again with a new build. *sigh*
S3 was simultaneously more engaging and with decent graphics, once modded. But the laaaaaggggg! That's what brought me back to S4: smooth gameplay and building. Plus I really prefer the neighborhood concept over an open world - it allows for much more details.