Grocery tourists, which countries in the world do you think have the best supermarkets?

Those who love to check out the supermarkets of any country you go to, which countries in the world do you think have the best grocery stores? And what about them was so great? Which snacks did you pick up? On my list so far I have Japan, Korea, the US, France and Italy, but looking to broaden my horizons. Have heard that supermarkets in Germany, Mexico and Singapore are pretty great but keen to hear from those who have been!