I am an empathic metamorph - a description given to a charactor in an episode of Star Trek Next Generation. Who I am and how I feel varies depending on who I am with. I get along with just about anyone.
I also somehow recognize, respond to, and reflect back to a person their own good traits. I used to think of this as an ability to see the truth about people, but modified that when I came into contact with some truly evil people - I found myself shutting down emotionally, and somehow to them I became invisible.
Hence my description of myself as a mirror. Mirrors reflect light. Darkness is the absence of light, so I can't reflect that, though I can show it by virue of a lack of reflection.
Also, we can only see our own faces as reflections - we can never look directly into our own eyes, we can only see our faces as reflections from another object separate from us.
It's interesting to be a mirror interacting with people. One person looks directly at me and I respond to them - they see something of themselves. Two people can see each other indirectly in my presence: I show them each something of the other.
But it is also a lonely thing. Is there a 'me' in the mirror when no one else is there?