Fried Chicken and Sushi 344 Japanese people are so quiet. Most of the time!

I know that people everywhere are usually quiet on the subway but they seem quieter to me in Japan.  Going to the movies there would shock me because people would sit so stiff and wouldn't react to anything going on on screen!  Anytime Japanese people had to express "emotions" it would always be through shouting out at the top of their lungs!  Does anyone out there know why?