It seems there is still a remaining Puritan value in many US born citizens. This topic on FT reminded me of an article of a study, which also goes hand and hand with the Americans who have very long work hours compared to many other countries. In my work life 50-60-70 hours a week was the norm. Being nude anywhere but my home (or hotel room) was not.

http://www.nytimes.com/2012/08/05/op...l-puritan.html

My mother was from France. The woman never wore underpants her whole life.
I, her American born daughter, even wore underpants under my long pajamas and for some reason this angered her. She never won that battle.