Why do People Wear Masks?

Hmm, interesting question. Some would say people wear masks that can be seen and those that are invisible. The invisible one is for deep thoughts and could take me forever to answer that one. But people wear visible masks for health reasons, such as to prevent infectious airborne diseases to be spread to other people. Some wear masks if they have allergies, to help prevent an allergy attack. But masks either visible or invisible, both serve to cover something up for a certain reason.