Most therapists agree that our self-image is initially formed by the response of others. It is as though parents and other authority figures are holding up a mirror to us. If we see affirmation in their faces, we are likely to think highly of ourselves.
If their facial expressions are unfavorable, we begin to think negatively about ourselves. It's probably a little more complicated than that, but this is part of how our self-image was initially shaped.
Well, we are also image-makers in the lives of others. When the impressionable people around us see our face, what do they learn about themselves? Do they read a favorable or unfavorable impression of themselves on the mirror of our face? Are we giving them a positive or a negative image of themselves?
Watch your face. It is a mirror.