Before mirrors, humans most likely perceived their reflections in dark pools of water (see Narcissus). Later on, cultures developed methods of polishing stone, metal, glass, and chemical combinations to form modern day mirrors. Humans have been concerned with their appearance for centuries past, present, and most likely well into the future. As more advanced methods of reflection are introduced, perhaps we will be able to see things about ourselves previously left undetected...
Some animals are capable of recognizing themselves in mirrors as displayed by primates, dolphins, elephants, and infants (as opposed to cats, dogs, lizards, and most birds). The discovery of 'self' is both amusing and critical to the development of understanding others (not self). This basic understanding of others leads to empathy. Empathizing with others means that one shares or is familiar with the emotions and feelings that others experience. This is important to relating to humans of all walks of life. If one can relate, then there is genuine hope that care, concern, and peace is achievable for one's compatriot.
Appearance. We're told to not care about what others think about us, yet society conditions us to follow social norms in order to avoid being branded an Ωutcast. We follow fashion trends in clothing, cars, styles, and culture. When we deviate from these social norms, we risk embarrassment, shame, and exclusion for fear of being singled out by the 'herd'. If we practice fitting in, then we benefit from the strength shared in groups. Ultimately, one must ask themselves if they value the cost of 'fitting in' more than the price of being an individual. If the freedom to express yourself as an individual unfettered by communal, familial, religious, or any other social pressure appeals to your character then a price must be paid. This freedom comes at the expense of forfeiting one's vanity.
The good news is that being free allows one to experience life on your own terms. This means that your happiness comes from within instead of external validation. Beauty fades. Money comes and goes. Material possessions can be lost or taken away. Having these 'things' can be nice, but basing your worth and happiness on them is like building a sand castle on the shore of a beach; the tides of time will eventually wash it all away.
“The great use of life is to spend it for something that will outlast it.”
― William James
The accounting system for taste is highly subjective. What passes muster for some is barely tolerable to another. "To each their own" is said in response to such decisions. In pursuit of true freedom from societal dependence, one must learn to tune out the noise that society whispers in your ear coercing your conformity and soliciting your submission. This means not being afraid to leave the safety of the herd in order to develop inner strength and the independence to lead your own path...
“Man surprised me most about humanity. Because he sacrifices his health in order to make money. Then he sacrifices money to recuperate his health. And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived.”
― James J. Lachard