Our life is impermanent, like smoke or water, like grass or flowers. Our life appears, then disappears. Human life means worry. But human life also means, don't worry. If you understand impermanence, everything is okay.
Problems appear because human beings always want more.
This is a very important point. In elementary school the students learn to Study and play. They learn about their country and its boundaries. You are born into this world. In childhood, you are your mother's child.