Smile is the most fluid and rapid facial expression, spreading from eyes to the corner of the mouth. Indeed, it is the light on the face, with which the eyes look brighter all of a sudden and the teeth between lips shine more. Just as we are unable to keep the lightning as the replacement of the sun and the moon high in the sky illuminating everything, we can’t transform the smile into a fixed and collective expression. Once advocated deliberately, the natural humor becomes artificial. That is why humor isn’t something that can be promoted either. Otherwise, the spontaneous would turn out to be the imitated, and the flexible would be the rigid.