The shalow evolution

Subtle changes on our face can make a comparative larger impact on others. We are exquisitively keen on physical variables such as the size of a nose, lips, colour of skin and a person's height. For instance, one or two centimeters matter in human culture.
However, other features meaningful for better and lasting relationships are kept hidden from immediate assessment.
Someone's inner truth requiere time and study to be acknowledged.
Why so?
Why have we developed such a sensitive competence to recognise a face in a million, yet we hardly know how to evaluate other people's mind?
Why can we recognise ourselves in a photograph, yet we hardly know ourselves?