I think that we can eat many kinds of food in Japan and one of the most delicious in the world.People normally have 5 tastes that we can distinguish. They are "Sweet, Salty, Sour, Bitter and Umami(savory) ".Different kinds of foods are put on the table in Japanese homes. We bring in a lot of other countries food cultures,as well.
I don't know if this fact is a reason.However,Japanese especially seem to be able to distinguish "Umami" or other complicated tastes.Most Japanese food is natural "Umami" food.
(It is said that our taste is determined until 7 years old.)