Every single thing we do and learn in our lives becomes a part of us, our karmic experience. Einstein taught us there are no straight lines in the universe, therefore everything we send out returns to us, both good and bad. There is no escaping this universal law. Every thought, word, and deed puts energy in motion for either positive or negative return. Even though we might not see the effects of good deeds immediately, or might not be caught for bad actions at the time, there is no escaping the law of karma.
The clarity of our intention determines the intensity of the resulting karma. For example, if we intend to harm someone, the karmic result is different than if we harm someone unintentionally. How do we choose to pave our path with positive karma rather than negative karma? By monitoring our speech and our thoughts we can prevent ourselves from sending negative energy to others, which is always harmful to them and therefore to us.
When we misuse what we are given in a lifetime, we will not have it available to us in the next lifetime. Eventually, we will have to experience what we inflict upon others.
We all should remember that everyone does the best they can with the personality and circumstances they have. We all struggle through our difficulties and respond to them according to our personality make-up and experience. Holding this understanding in consciousness will help us to develop compassion.