Karma is action. Non-virtuous actions result in suffering, and from virtuous actions comes happiness. For every good action we put out there is an equal good action coming back to us, this balance is a natural law. For every action that has a harmful effect to another being , we will receive harm in return. You may be saying right now, but I live a good life, and all this bad stuff keeps happening to me. This is the result of you bad actions in your previous lives. The same is true for those who we say have the Midas touch, or the student who masters a subject without effort. This is the result of actions in previous lives. We don’t have a preset time allotted to us on this earth, our time here is limited. If we continue to do harm we can be reborn in a lower realm, such as the hungry ghost realm, or the animal realm. There is a Tibetan story of a village beside a lake where the citizens spent their days fishing. This had been the way of life for generations. One day a master who had a gift of clairvoyance or clear sight came to the town. He observed this and said “All I see are the people and fish changing places”. The fishers were reborn the next life as the fish, the fish as the fishers, each eating the other in turn, caught in a repeating cycle. In our own relationships, how often do we take from others, without giving back equally? We get someone to like us, to say to others how nice we are, yet give nothing back, till one day we say I grow tired of you, I need another to sing me new songs of praise. Then we wonder why we never have a lasting relationship. As we hurt others we will be hurt in the same manner, if not today, then tomorrow or the next life. If we accumulate enough bad karma, we may have to wait till we are reborn in the human realm to burn off our bad karma. There are many stories about karmic connections lasting hundreds of years, before balance has been achieved.