But has anyone noticed the "pajama trend"? A Tesco supermarket in the U.K. has, and has instituted a dress code in response: Footwear must be worn at all times and no nightwear is permitted ...

A man stands in a pair of striped pajamas in a 1927 drawing from French fashion magazine. Initially, pajamas were marketed only to men. A key to their success was that they were seen as more manly ...