What Is Karma and Why Should it Matter to Us?

Karma is crucial to our development as wise, caring, and loving human beings because, if we act out of a non-harmful intention, we predispose ourselves to act that way again.
In other words, we plant a behavioral seed. We begin to form a habit.
Conversely, if we act out of a harmful intention, we predispose ourselves to act that way again, making it more likely that the next time our behavior will be harmful....
And so, by responding with kindness, compassion, and generosity, we are turning ourselves into a person who is kind, compassionate, and generous. We are forming our character. This, in turn, has a positive effect on the world around us....

Karma is based on logic. It is an unavoidable consequence of our creations. When we create anything, we also create other things which might not be what we intended.
If I get angry and with another harm, then I create a state in which I am harming another and another is harmed.
I create a state in which I am happy with the suffering of another. But also create a state in which another is unhappy and suffering. I create a state in which I am joyful that my enemy is justly harmed. And a state in which another is resentful and angry that they have been wrongly treated.
This relates to the  games of life.
In whichever game we play certain causes and effects arise. And certain rules are required.
So when we create anything, whether a good intention or a bad one, other side-effects are necessarily produced.
Imagine a world where no one harmed another in any way.
And I harm another.
I create someone who harms another and one who is harmed. This did not exist before.
But now the world contains suffering.
And in the present life, or in subsequent ones, there are those who suffer and those who harm.
And I, and others, play all these roles.
In the beginning before harm was created, it was impossible to suffer.
But when I do harm then suffering exists to my detriment.
Of course, I am not alone, and others who create harm also create suffering and we continue to play our games in a world with suffering.
Now after many aeons, we wonder why there is suffering. And why there is harm. Yet this is the result of our own creations.
However when we intend to UNDERSTAND, then we create UNDERSTANDING and that which is UNDERSTOOD. These may be desirable states.
When we wish others well, then we create the state of being wished well. Therefore, this may be acceptable to all.
When we create the state of BEING HAPPY, we also create, the state of BEING HAPPY (the same?) which is acceptable to all.
When we create the state of RESPECTING ALL we also create the state of BEING RESPECTED which is acceptable to all.
We need to create states that are acceptable to us in all their forms. Actually, the so called 'Golden Rule' is a rule for creating good karma. It has never been expressed properly, but it is the rule, 'Do to others what you would like them to do to you.' We need to capture the idea of the law rather to be bothered by its wording.