The ability to recognise oneself is held as a sign of a higher mental ability. It is not strictly limited to humans, elephants & dolphins show this ability for self recognition to some degree. Associated with social complexity, self recognition, as shown above, emerges from distinct species.
You know you are your reflection whilst simultaneously knowing it is only a reflection. Seeing one in what one is not, is a powerful dynamic of the individual and community. It enables vicarious existence; a thrill from victory an Olympic spectator feels, empathic pain brought about by a photograph of suffering, endurance welling up from unreal stoicism. Perhaps this is an essence of altruism.
Identity is created from cogs like these, and maintenance, by scrutinising culture for role models to inspire effort, is a function of a healthy mind. It should be known that positive and negative role models are important. People reach for a perfection beyond humanity, and people fear a cruelty beyond what is possible. Is it easier, when in a foul mood, for effort to come from seeking to avert fulfilment of nightmares?
As one person recognise them self in something they are fundamentally not, so to does a community. Modern Germany has a great many taboos formed around Nazi Germany. The community knows it was them, and knows it was not them. The imperfection inherent to us all prevents this from being perfectly perceived or completely ignored. As in the time of cavemen it was better to know where the lion prowled than where the flowers bloomed, humanity has a natural pessimism which fills our culture with memes of curses more than blessings. Hopefully it helps those escaped from a real hell that the flames were never as high as the righteous dread.