Nancy Napier talks about the importance of accepting the disowned parts of ourselves in her discussion of the shadow in her book, Sacred Practices for Conscious Living. Here's an excerpt:
And, so, we begin our journey home by deepening our awareness of the most hidden aspects of ourselves that comprise our shadow. For each of us, the shadow consists of disowned aspects of our personalities - positive as well as negative - that had to be hidden when we were young: those elements of our natural self-expression that were disapproved of, punished, humiliated, or otherwise judged as unacceptable by the important people in our lives.
Disowning parts of the self is an unconscious, self-protective mechanism that allows us to fit in as we grow up. The shadow doesn't exist only for people who come from troubled families or for individuals with particular kinds of psychological problems. The psychological dynamics that create the shadow provide a necessary adaptation to our interpersonal world. We all participate in creating shadow selves that contain whatever qualities we were not allowed to express openly.
When we don't acknowledge our own wholeness - when we continue to push away parts of ourselves that are a source of shame, fear, or anger - these parts erupt unexpectedly and create all manner of difficulty. For example, we may unconsciously make enemies of those who act as the representatives of the very characteristics we can't tolerate in ourselves. We create a world of "us versus them," in which we spend an inordinate amount of time trying to get other people to change. In fact, if we would only stop and look in a mirror, we would discover the source of much of our discomfort and displeasure staring back at us.
It can be very scary to look in the mirror if we're afraid we'll be overwhelmed by what we see. That's why the meditative process is so very helpful. If we are meditators, we know what to do with thoughts so that they will not be overwhelming. We can notice them, accept them without judgment, let them go, and return to the meditative support or, if we're not engaged in formal sitting, to whatever we're doing in the present moment.