I keep my chaos reigned in. I tend to have interesting relationships. For example, my last family, which was tragically lost because I forgot to back up the saved game, started out as a married man and wife. Simply enough, right?
One day, the husband cheated with the maid and the wife had an affair with a woman vampire. After their marriage blew up, he married the maid and had a daughter with her. The now ex-wife (who wasn't aging since she had also become a vampire) grew close with the daughter of her ex-husband and his new wife and they got married when the daughter came of age. Both couples lived in a giant house with no more infidelity.
This is the kind of chaos that keeps me interested in my families :) My sims will at times have children, but they will almost always move out at some point while the parents keep themselves young and continue the story.