Karma is both good and bad for your sim. Every time at midnight your sim with earn Karma points. If you have been granting your sims wishes frequently then you earn good Karma points. If your sim is getting neglected, or sometimes by just happenstance, then your sim experiences bad Karma. Bad Karma can range from your household appliances breaking to a fiery meteor shower than can burn down your house. Good Karma ranges from being able to resurrect your dead sim to speeding up their learning process making skills progress faster. You can unlock different Karma powers by completing challeges in the game and some challenges require different Karma powers to be unlocked.