  The way I see it, there is no real karmic justice-- at least not in the way most people expect it to be. Instead of rewards for good things and punishments for bad things, I see it as sort of a way to equal out good and bad things in a person's life.
You see, life is like a rubber band stretched taught between your fingers. Every time something good happens, the rubber band is pulled tighter. For instance, if you have a good day: you spend the day with your crush, you recover from an incurable disease, you become the queen of your own country-- all these merit another yank on the rubber band of your life. And then, when you start to think that maybe everything will go your way for a change... SNAP! All of the positive events break the strained rubber band and it'll come flying back to hit you in the face with as much negative force as it built up with all of the happy goings-on.
It'll all come back around with counters to everything pleasant and then some-- come back and hit you right in the eye. That, my friend, is the rubber band theory. 
