Give an example to explain what "every grass and tree can't report spring"?

In Meng Jiao's poem, it is said that "only an inch of grass is a little sentimental, and I get three blessings in spring", mainly because it is difficult to repay my parents' kindness when I was a child. Most parents in the world love their children. They pay too much for their children, and children often give them less than they give us. Just as a mother has to endure great pain when giving birth to a child, it is regrettable that there are more loving mothers and fewer dutiful sons in the world.