It is not the eyes alone that are the windows to our soul but our faces, whose fluid expressions unconsciously reveal our stream of consciousness, so that, to hide our souls, we resort to putting on fixed expressions, as masks.
In mirrors, people seek to see themselves as others see them. But, as fairytales tell us, mirrors lie. We can never see our face in a mirror but only our masks. As we fix our eyes on our reflection, it becomes impossible even to glimpse how our face looks when our eyes wander freely, or when it reacts to our thoughts, or to other people, or to the world. Mirrors are more insidious even than that, for they show us a face radically different from that which others see.*
Though photographs and videos can show us our face free from the misrepresentations of mirrors, they too mostly lie: unless manipulated by a skilful hand, a lens does not see a face as does an unmediated human eye.
Mirrors, photographs and video, by encouraging self consiousness, coax us into putting on masks. People in the public eye—filmstars, famously—are forced to live much of their lives behind their masks. Since the advent of the smart phone, alas, we all now live in the public eye—especially the young.
The curse of self-consciousness is that we turn in on ourselves; the more we wish people to see our face as we want them to see it, the more we trap ourselves behind ours masks.
addendum: unconscious masks
Some masks we wear unconsciously, most of which were adopted when we were children. Some were passed on culturally—when, for example, we unconsciously began mimicking an expression of a person that we admired or found funny. Others, we inherited from our families as we unconsciously mimicked the face of a parent as they expressed a strong emotion or did something as subtle as chew their lip as they concentrated on something. Because our face naturally resembles those of our parents, these unconscious masks may be nearly identical to theirs. Such masks may descend to us from who knows what ancestor.
*unless someone is standing by our side looking at our reflected face as we look in a mirror