Interesting how some people have noticed changes in autonomy due to likes/dislikes and others haven't.
Likes singing -> autonomously practices singing - @EgonVM
Dislikes video games -> does not autonomously play cell phone games (I forget who noticed this one)
Sims do not autonomously gravitate toward things they like and do not autonomously avoid things they dislike - @SheriSim57
@RavenSpit That's already in the game! It took me a couple months of playing to find it though. If a sim enthuses about a specific interest that the other sim also likes or has a certain amount of skill in, like Enthuse About Cooking or Enthuse About Favorite Author, the result is as you describe, an especially happy interaction and relationship gain. If they enthuse about something the other sim dislikes or has no skill in, the relationship will decline and there's a chance the other sim will become Bored.