As a fan of online literature, I can't give general advice because it depends on many factors including family, culture and social background. However, in some cases, it may be beneficial for children to understand the dark side of human nature and society. Letting children understand the dark side of society can help them better understand the society they live in and prepare them for their future growth. This would make them understand that there were problems of injustice, deception, corruption, and so on in society that could affect their own lives. Letting children understand the dark side of human nature can help them better understand themselves and others. This would allow them to understand that selfishness, greed, jealousy, violence, and other problems in human nature could affect their behavior and interpersonal relationships. However, it should be noted that the dark side of society should not be directly told to children. Instead, stories, poems, or other forms of art should be used to help children better understand these problems. At the same time, parents should also provide positive education for their children to help them establish correct values and codes of conduct so that they can thrive in society.