Feeling socially rejected actually physically hurts. It always feels terrible, and this is by evolutionary survival based design. In order to understand the impacts of social rejection, it's important to consider different factors:
We all have hunter gatherer tribal ancestors who depended on being members of the tribe in order to survive, and they experienced the possibilty of tribal rejection as a treat to life by starvation in isolation.
Because human beings are a highly adaptible social based species, we adapt to survive generation by generation, with DNA changed by stress and passed along from mother to child inutero (Epignetics) to ensure the next generation's best chance of surviving the crazy tribe they're being born into.
By default, our ancestors would have had to conform to the expectations of the tribe inorder to survive, and because survival is our top priority this gene expression got passed along, building generation to generation to where we are today.
Instead of looking at it as though we still have these influences in us to quash, realize these influences are what have allowed the human species to survive all the way through today, and are at the very core of our genetic make up.
Rather than attempting to quash them, we will do far better if we learn what they are, release the felt need to personalize the fact we've experienced them, consciously exchange fear or anger with a sense of curiosity about the experience, and how we can most efficently work with our prehistoric survival system activating from modern day stressors.