Many people who feel unworthy in social situations are focused more on how they think they look, and how they think others perceive them rather than how they are. These people don't trust their own judgements, and seek validation through others, which leads to identity confusion, and let-downs because others rarely see us how we see ourselves or how we think we really are. Just being yourself is the best you can do, and others will be attracted to you because of it even if you pick your nose a lot. My perspective is that it weeds out the disclaimers whom you can't please, anyway.