All actions in life have a cause and effect. What we say or do is caused by something and what we say or do causes something. When we look at our actions (behaviors), we can mindfully ask, “What does each cause?” Even though we will probably never know all of the effects of our actions, the basis of Buddhist morality is that acting in unskillful ways leads to unhappy results and acting in skillful ways leads to long lasting happy results.
Karma is a term that refers to how both skillful and unskillful behavior affects an individual over time. Karma is not punishment or retribution but simply an expression of the consequences of our actions, both skillful and unskillful. It is not a simple, one-to-one correspondence of reward or punishment. It is just important to know that unskillful behavior puts you at risk for unhappiness. So it is in our best interest to live a skillful life.