We humans are social beings. We come into the world as the result of others’ actions. We survive here in dependence on others. Whether we like it or not, there is hardly a moment of our lives in which we do not benefit from others’ activities. For this reason it is hardly surprising that most of our happiness arises in the context of our relationships with others. Nor is it so remarkable that our greatest joy should come when we are motivated by concern for others. But that is not all. We find that not only do altruistic actions bring about happiness, but they also lessen our experience of suffering. Here I am not suggesting that the individual whose actions are motivated by the wish to bring others happiness necessarily meets with less misfortune than the one who does not. Sickness, old age, mishaps of one sort or another are the same for us all. But the sufferings which undermine our internal peace—anxiety, doubt, disappointment—these are definitely less.
The Pocket Dalai Lama, pages 6-7.