How does an avoidant attachment style develop?
Our attachment styles developed in our early years in response to our environment, and specifically to help us deal with how we felt for our primary caregiver (usually the mother). An avoidant attachment style is in response to an unconscious message that we are not wanted. Since the world is composed of our primary caregiver at that age, and we know they are necessary for our survival, it is terrifying to not feel cherished by them.
Rather than let the neglect paralyze us, we mould ourselves to not need attention, love and nurturing, to the extent that we avoid meaningful intimacy altogether, or seek it but always mistrust it. This keeps us stuck in unfulfilling patterns of behaviour where we self-sabotage the moment real closeness starts looking like a reality.