People do shit all the time that will eventually affect their lives. You do a good thing, a good thing will happen to you. You do a bad thing, a bad thing will happen to you. You may not pay for it or benefit from it in this life, but you eventually will. Sounds pretty damned simple to me. I am a firm believer in this concept.
There is another side to karma that I have discovered. It has to do with what you say. Everyone has his or her own little sayings. "No shit.", "What a pain in the ass.", "This sucks.", "I'm so broke I can't afford to pay attention.", etc… I have discovered that if you continue to say things like this, your brain, in league with karma, will subconsciously find a way to make what you are saying a reality. Without knowing it, you are programming your own brain to make these negative things happen to you. You literally are writing the code in your brain. Sounds crazy, huh? I don't think so. I have seen it happen many times.
Case study #1: I have an uncle who lives down south who had surgery. JC was always famous for saying "no shit". It was one of his favorite phrases. One of the conditions for his release from the hospital after his surgery was that he have a bowel movement. Know what? He couldn't. He eventually did, but it took quite some time.
Case study #2: Some of you know the trials and tribulations I have endured in the last nine years. I moved to Oregon, and initially couldn't find a job. The first job I find, my first paycheck bounced. I get a divorce from the evil one and get financially raped by the courts. I lost my job (a damned good one!) and was unemployed for almost a year. I owe taxes, federal and state, in excess of $2000. Wanna take a guess on what one of my favorite sayings is? Besides "fuck you in the neck", I mean? "I am so broke I can't afford to pay attention." Between my brain, and karma, that is exactly what has happened for the last nine years. Needless to say, that phrase is out the window. Adios!
Karma is neutral. It is the ultimate input-output device. You get what you put in. Mind what ya say kids, it might just fuck you, and not in a good way.