http://www.youtube.com/watch?v=E4HGfagANiQ

Ultimately a science video, but it has some interesting social-psychology points.

Why are humans afraid to be naked (modesty)? Embarrassment is a social emotion, only experienced when others are around. Embarrassment is also an indicator of a healthy brain. Being embarrassed relates to having reduced pride and respect for others' feeling and well-being as well as a desire to be liked. Flirtation and playful teasing can evoke embarrassment in another person, proving that they are a quality person.

There are a lot of other interesting statements in there if you watch the video from a TRP point of view. I don't want to write them all out when there is a good video explaining them all anyway, so take a look.