Altruism mainly corresponds to egoism. Egoism means that no matter what you do, the first consideration will be to be good to yourself, and do it if it is good. Even some people do it for their own benefit, even if they hurt others. This is a sign of selfishness. And altruism, generally speaking, is whether it will be good for others.
People who are always altruistic are positive, optimistic and confident. Their hearts are full, happy and rich, because they are nourished by our "altruistic heart" all the time.