I lived in Tokyo for nine months and mostly love Japanese food. I will defend sushi and sashimi to death and probably only cook my fish back home medium rare. There is NOTHING like a hot bowl of ramen and a cold beer on a cool winter's day. And the aforementioned nashi pears are LUSH. However, natto aside, I did have a few odd, a few revolting and a few tasteless dishes and without exception they involved tofu, daikon or both.
God, forgot daikon. Plain nasty although it does generate some impressive turbulence.