I love following their wants in general. I've done things I wouldn't even think of due to that.
Something even more interesting I've found is some sims' relationships just don't work. They will actually start arguing over nothing. I had my sim worry about money to his wife and she got mad at him, turns out she didn't even want his apologies and just about every friendly interaction had a negative outcome, even days later.
They ended up getting a divorce and the teen son disliked his new stepmom.