Karma is often understood as a relationship between cause and effect. The energetic undertones of the actions you take will be returned to you in kind later in this life or the next. However, I do not feel it is just that.
On a universal level, Karma is also interpreted simply as the force that maintains balance between everything ‘good’ and ‘bad.’ From the individual’s perspective, Karma is what energetically binds you to that which occupies your conscious attention. It connects you with what makes you happy, sad, annoyed, angry, upset, anxious, and so on. The things that you love occupy your conscious being in the same way that you are gripped by the things that you hate. What you are unable to let go of becomes a part of you.
When you do somebody wrong, you are creating a powerful karmic link. You should ask yourself first, “Do I really want to walk hand in hand down eternity with this jerk?” — from ‘Finding the Heart Sutra’