(man bowing to nobody as part of his work ritual)
The rules of Japanese manners and etiquette are somewhat complex. They're deeply embedded in Japanese culture, thinking and language.
The good news is that it's easy to avoid seriously offending anyone. First, use some common sense. Second, try to avoid these embarrassing situations.
1. Toilet Slipper TragedyThe single most embarrassing thing you can do in Japan is to wear toilet slippers outside the bathroom. Japanese culture demands the separation of the clean and the unclean. In Japan, toilet slippers are considered the dirtiest objects in the known universe.
2. Helping With Your ChopsticksJapanese ohashi (chopstick) manners are more complex than you might expect.
If you see someone struggling to pick something up with ohashi you might be tempted to help them with your ohashi. Unfortunately this act resembles a funeral ritual in which cremated remains are transferred to an urn with ohashi. It's considered a morbid thing for two people to pick up the same thing with chopsticks.
So the next time you're struggling to eat a fish with chopsticks in Japan — you'll know why no one helps you.
3. Picking SakuraSakura petals are a national symbol of Japan. They're considered more beautiful (according to Japanese aesthetics) because they're impermanent.
Sakura bloom in brilliant color and then fall to the ground in a few days time. Many well known Japanese poems, books and songs use this as an analogy for change and mortality.
Sakura falling is a nostalgic image for many Japanese. If you pick a sakura petal then it doesn't get to fall. People will think you're a culture-less thug.
4. Drinking Before KanpaiIn Japan, it's customary to kanpai before drinking. This ritual is never dropped even in very small or large groups. Drinking before the kanpai makes you look selfish, antisocial and undisciplined.
(notice one beer is half empty)
5. Polluting the OnsenOnsen isn't a bath for cleaning your body. Onsen are communal baths for a relaxing soak. This is the main reason that onsen require nudity — you're supposed to bathe (with soap) before getting in.
If you skip cleaning before getting in people may be disgusted. If you're at an onsen resort and it's your third time in a day into the bath — you can cleanse yourself quickly with just water. There's no requirement to take 5 soapy showers a day.
6. The Bow HandshakeWhen you're in Japan on business you should introduce yourself with a bow. In some cases, your Japanese counterpart might assume you don't know how to bow and go to shake your hand. This can result in a confusing mix up where you end up awkwardly bowing and handshaking at the same time.
If you're in Japan on business you should try to insist on a bow. Shaking hands in Japan just makes you look dumb. Imagine a Japanese business man bowing on a business trip to Texas — it's the same thing.
7. Hey You!The word you is pretty common in English.
There's also a word for you in Japanese (貴方 anata). In fact, there are many Japanese words for you. Be careful using them.
In Japanese, it's polite to address everyone by name in most situations. It's also necessary to use a polite suffix (usually san).
By using the word you — you're possibly indicating that you don't respect the person enough to use their name.
The exact rules on when you can and can't use "you" are complex. As a rule of thumb try to use the person's name as much as possible (in place of you). Alternatively, you can often just drop the personal pronouns from your sentence because they're usually understood from context in Japanese.