One can get a full conception of the character by studying the full countenance and not a part only. The study of a part always gives only partial knowledge. Complete knowledge is gained only by a study of the whole. Keen observation with the desire to understand helps a person to read the condition of man's mind, his nature and character, yet the view is often colored by the personality of the one who sees. His favor or disfavor, his liking or dislike, stands between the eyes of the one who sees and the one who is seen. Therefore, sometimes, innocent people have a better understanding of a person than clever people with deceitful minds do. There is a saying of Sa'di, "O my subtle cleverness, Thou often becomest my greatest deceiver."