Some pain can be hung on the face for people to know, and some can only be buried in the heart and endured alone. Sometimes, what is engraved in the heart is more painful than what is written on the face, because it damages your bone marrow and spirit. We often pay attention to those who are in pain on their faces, and we are generous and generous; but we will ignore or even be indifferent to those who are in pain in their hearts. The most difficult thing in this world is not to lend a hand, but to walk into the hearts of others.