Children can be good or bad, admirable or foolish, just like adult human beings. But sayings and stories are told that emphasize one side of this contrast or the other. When we are encouraged to be like children it often means imitating their trust and naïve openness to the world. It’s very different to recommend or imitate silly childish thought and behavior.
Some people seem to act and think like children all their lives. This too comes in two forms. Their delight is contagious, their simple approach to the world is attractive, their ignorance makes complex issues disappear. Artists are praised for their delightful play in various media like precocious children.
People usually mature into adulthood. Then they try to train children to face the challenges of life. Education in science and technologies helps but more valuable is learning about the traumas of human life and consciousness. It is dangerous to live childishly in the adult world.
Childlike trust in adults and adult society is childish. Growing up means dealing with the anger, fear, and menace of other people, learning to distinguish among the crowd. Childlike trust must be modified by social awareness, and techniques for dealing with failure as well as success. Pouting when we do not get our own way in life does not help.
While enjoying the child in ourselves and others we must beware of simplistic approaches to the serious factors of living. As often said: Grow up!