Japan is a great place, really, with clean streets that are always safe to walk down at night, an excellent public transport system, and toilets that wash your butt for you. The people are nearly always polite, unless you get between an obasan (middle-aged housewife) and a sale item she's got her eye on in the supermarket, and there are many amazing foods to discover, like "aspara-bacon" (asparagus wrapped in bacon), a favorite dish of mine at izakaya restaurants. But there is one problem, brought about by Japan's homogeneous society in which 98% of people believe themselves to come from exactly the same genetic stock, which can be thought of as "tyranny of the masses." The Japanese think bread should be white and fluffy, so don't expect to find a huge selection of cracked wheat, oat and other types of healthy bread in supermarkets here. They also tend to like thick, creamy milk with 4.2% milkfat or higher, and it's not uncommon to find no lowfat milk available in the store -- and just forget about ever finding skim milk. Most Japanese cities require trash be separated, with moeru gomi (burnables), plastics, aluminum and steel cans, PET bottles and so on all being put out on different days from 6-8 a.m., which is kind of hard on people like me who stay up late (since I have to overlap my day with the J-List San Diego office). Finally, the Japanese often don't "get" non-standard food lifestyles, and if you're a vegetarian or need to avoid rice or caffeine for health or religious reasons, it can be a bit of extra work.
Of course, can you imagine a bunch of self-entitled foreigners in America whining that Americans don't do things exactly as they would like? They wouldn't get very far.
Japanese love thick, creamy milk.