1) Japanese people's reluctance to express their opinions and their general naivete (i.e. lack of critical sense)5) 5-month-long muggy summers
I'd put this on the good list. Nothing better than a nation of people that mind their own business and don't get up in your ***.

1) The shocking ignorance about the rest of the world (or even about Japan)
Go to America for a while. Even more shocking.