Karma the mechanism by which we learn.
You will sometimes hear it used as if it were a punishment. That you will accrue bad karma for something, and have to pay. That you have a karmic debt of some kind or another.
In a way, all of that is true. But, I think, it's not as if there was some vast Karmic Ledger, with Someone giving you black marks for the bad choices, and gold stars for the good ones. It's all natural consequences.
It's the same thing that gives you a burn if you touch a hot stove. No one is punishing you. In fact, it works the other way around. The reason touching the stove is a bad choice is because of the burn! If touching the hot stove didn't cause harm, then it wouldn't be a bad choice.
In just the same way, it's not that Someone has arbitrarily set up a list of Good Things and Bad Things, and if you do a Bad Thing you will get punished. It's simply that harm makes a choice a bad choice, and harm also hurts you. If the harm was to someone else, then the Three-Fold Law is what makes it rebound so, not some Judge in the Sky.
So it follows that you can avoid the pain by learning as quickly as possible, or even by learning from watching someone else, which is why they say that "Wisdom erases Karma."
I learned about the stove because I was told over and over not to touch it, and I saw my baby sister get a bad burn from touching the open oven door for just a moment. That was enough for me. But there are some mistakes I have to make three times. Once because I didn't know it was a mistake, once because I didn't believe it the first time, and once to see if it would keep turning out like that!
I believe that we decide for ourselves what lessons we want to learn in each life. And one I have learned is to learn as much as possible from each unpleasant lesson I encounter, so I will never have to do that again!
The only reason Karma gets confusing at all is because it goes on from life to life. But then, so do we.
I had a student once who told me it was quite unfair that she would have to suffer because she made a mistake in a life she couldn't even remember. She maintained that wasn't her, and it wasn't fair!
I explained it like this. Think of your different lives as different sweaters. We go to school every day, and every day we wear a different sweater. Now say that you were working on quadratic equations one day, and you couldn't get it. The next day, when you go back, you will still be working on quadratic equations. The fact that you changed your sweater has nothing to do with it.
We aren't our bodies; we just wear them to the school of this planet. Each life we are given the gift of temporary amnesia, so that we won't fall back into the same behavioral rut. If you were trying to break a habit, wouldn't it be nice to not remember it at all, and start with a clean slate? Well, that's how I think it is. We get a new chance, with no old memories to mess us up. But after we have finished the school day, we go home. And there the amnesia is lifted, and we can tell what we have learned that day. If there was a lesson we wanted, but we didn't learn it, we go back the next day and repeat it again. And again, until we get it! But no one is making us do this, it's our choice.
Don't think of it as school like elementary school, where you are forced to go, and have no control over what you are learning. Think of it as college, where you want to go, and choose your courses.
And learn as much as you can, with the help of Karma!