As a child, I often quarreled with my brother. And when I complained to my father, he always said, "Maya, don't get annoyed over unimportant things. Think of your future! You will grow up, your mother and I will grow old and die, and then you will find much support in your brother and he in you."
Of course, this helped little to cheer me up at the time. Moreover, because of the inherent uncertainty of the future and particularly of individual life spans, my father's prediction eventually turned out to be wrong.