We are essentially blank slates with some genetic predispositions toward certain behaviors. After birth, the tape recorder starts. Our minds record information. We learn to recognize our Mother's voice, to sit up, crawl, walk and eventually, how to deal with obstacles which arise in our lives. If we keep our minds open and we can come to see the virtue of certain actions and the utter futility of others. However, when we settle on a particular world view or definition of "success", our minds close and we look only for "evidence" to support our chosen worldview. We prejudice our interpretation of reality in order to suit our chosen world view. We rationalize, we stereotype, we accept "easy" answers to terribly complex problems and assert them as indisputable truth. I certainly believe we are our own worst enemy in many respects.
edit: speeelingsz