You all missed the real reason. Holding the hands behind the back allows walking and standing with a slight hunch forward. This relieves the nerve compression of sciatica, a common ailment of older people, especially men. It is possible that many who do this don't even fully recognize why they do it, but just that it makes them feel better.
FLASH Application. Online Application for an Insurance License. The California Department of Insurance (CDI) requires California resident applicants to first pass the qualifying license examination prior to submitting their license application.
Flash floods are the most common flood type in normally-dry channels in arid zones, known as arroyos in the southwest United States and many other names elsewhere. In that setting, the first flood water to arrive is depleted as it wets the sandy stream bed.