There is a song that says, "Plain is true ..." This reveals a sense of happiness-a plain life. For some people, this is nothing. Can this be considered happiness? But for some people in special positions, vagrants or outlaws, it is an unattainable happiness. Those who live a dull life every day are eager for another kind of happiness-energetic and exciting ... In fact, if one is willing to keep looking for happiness from time to time, one can see happiness in the changes of things, whether it is full of vitality or dead silence. Happiness lies not in material things, but in the mind.