Anything from an exaggerated distance between the eyes, a large hump on the nose, particularly small or large lips might be unacceptably distant from the platonic ideal. Small deviations from the standards go unnoticed in society or many be considered cute, unique characteristics. Large deviations are readily recognized, detract from the natural harmony of the face, and may be distracting. Gross deviations from the model of normal are considered deformities and may turn the subject into a psychological outcast. If people are asked to compare random pictures and decide which face is the most beautiful, they will select the one in which they can not find any fault.
Human beings are incredibly unique because of their facial features.
We are virtually the only species of animal that can recognize such a large variety of individual members based on their physical appearance, in particular their facial appearance. Then there are a myriad of expressions that can be generated from each of those basic facial structures. Facial expression provide a powerful tool of non-verbal communication that truly qualifies it in a classical sense of its own. Although some of us have a personality that tends to thrive on a unique appearance, in many cases others may feel that it draws undesirable attention to ourselves. For some people, their appearance may detract from the verbal or emotional message they are trying to convey.