By recognizing a favorable opinion of yourself, and taking pleasure in it, you in a measure give yourself and your peace of mind into the keeping of another, of whose attitude you can never be certain. You have a new source of doubt and apprehension.
Source: Human Nature and the Social Order, ch. 6 (1902).
-- Charles Horton Cooley, (Aug 17 1864-1929), US sociologist; He followed a socio-psychological approach to the understanding of society.