At some point, you've likely heard a conversation something like this: "I'm exhausted from helping out at the soup kitchen today." "Yeah, but that kind of work will bring you a lot of good karma." Or maybe seen the guy who cut you off in traffic get rear-ended just a mile later, and thought, "Karma just got you." Karma, we learn, is basically getting what we deserve, whether that's something positive, because we've done something good, or something negative, due to our poor behavior. But that's not what karma really is, or how it works.
Karma is a Hindu and Buddhist concept that teaches all of your actions, through a wave of successive incarnations, will influence your destiny. In essence, karma is retributive justice; you're punished or rewarded in a future life according to your actions in this one. The concept of karma can't be understood, and isn't valid, outside of reincarnation. Because karma plays out over a long time, over lifetimes. It's not something that is summoned up in the moment [sources: American Heritage Dictionary, Goldberg].