21. No tippingYou shouldn't tip in Japan. You may learn to like this. Most Japanese staff will consider a tip demeaning. You'll quickly find the lack of tips doesn't affect the level of service.
22. Reserving a seat with your purseIn Japan people reserve a seat at restaurants and cafes by leaving possessions on the table. This may seem like cheating when you're not accustomed to it. However, it's a well established local custom.
Japan is so safe that people sometimes use their wallet or purse for this purpose. Here a woman has left her wallet in plain view and gone to restroom.
That's not to say that purses aren't stolen in Japan. Drive by purse snatchings are a problem. Usually the thieves aren't out for credit cards and petty cash. They target shop staff who have a shop's daily bank deposits.
23. No blowing your nose in publicIn Japan it's generally considered rude to blow your nose in public. It's best to go to the restroom to do it.
The good news is that touts hand out free tissue paper on the streets (with embedded advertising).
24. Exotic foodYou will find that there's a big difference between Japanese food outside Japan and the real thing. There are at least 30 types of Japanese restaurant. Many varieties of Japanese cuisine are challenging for those with particular tastes.
25. Dangerous areasThere aren't many dangerous areas of Japan but they do exist. There are also areas where you wouldn't want to bring kids.
26. Smoky restaurantsJapanese restaurants (particularly izakaya and cafés) can be smoky. Some restaurants don't have non-smoking sections. However, things have improved a great deal over the past 10 years.
27. Baka gaijinBaka gaijin （馬鹿外人） means stupid foreigner. Japanese people don't say it much. It's said more by gaijin themselves to explain the behavior of some of their compatriots. For example, some gaijin incessantly complain about Japan in a bigoted manner.
If you meet a baka gaijin maintain a distance. They can interfere with your travel karma.