This is a gameplay mod idea that I just posted on another forum. It has to do with how objects and activities are all just as fun to every sim. And things like computers and tvs and woodworking tables are so 'fun' that everyone gravitates directly to them in a really artificial way...
The app would make the fun rating of objects NOT increase the likelihood of a sim doing something until they've already done it at least once. So to start with they'd be naive and everything would be just as fun. And the more you make your sim do something the more fun they get out of it. It'd be like they formed habits, and could be very different from sim to sim. It could be capped, so that the most fun something could be would be like the TV is now - that way it wouldn't break the gameplay, just give sims some variety.