Cheerfulness is, as it were, the sunny ray of life. This is the constant portion of none, and the word itself comprehends also a multitude of degrees and modifications. The sum of all is this — that man, ever from inward and outward circumstances, forms for himself a nature which is peculiar to him, and is the track on which his life glides. This is a beneficent arrangement of Providence, for no struggle after harmony and elevation is ever without effect.
— WILHELM VON HUMBOLDT