Finding yourself on the outside of things often leads to this emotional style. The perceived message is, "You're not like us." This feeling typically causes a person to stay on the edge of the action, reinforcing the feeling of exclusion. This may lead avoidance of groups in adulthood, or conversely, cause someone to revel in their outcast role.
If you feel excluded, learn to feel and challenge your fears by making efforts to initiate conversations, and learning to master your anxiety. Mindfulness will help you step back from thoughts that make you uncomfortable.