Rejection is probably the most common and common emotional injury shared by all human beings. The areas of the brain that showed increased activity while remembering the rejection experience were the same brain regions that work when we experience physical pain.
The experience of rejection today directly harms our need for belonging and the desire to be part of, who are descendants of the same need for survival. Experiencing rejection also damages our sense of identity and self-worth. The more exposed and vulnerable we are, the more unequal we are.