15 Unwritten Rules of the Japanese Office

I only started working in a Japanese office about 4 months ago. My office has a mix of Japanese people and foreigners, but still has an overall Japanese vibe to it. I found out very fast there are many things that are not okay in a Japanese office setting that I believe would be okay in an American office. I am still learning many things, but here are some things that I have already found out. 

1. Bring a small treat for everyone in the office when you come back from a trip. Make sure you have enough for everyone. You also need to distribute them on everyone's desks. When you are eating one, make sure you say thank you to the person who gave it to you and offer a small comment. 
2. If you bring your own lunch to work, people usually don't wash their dishes in the office, they usually bring their dirty dishes home in their bags. 
3. It is not normal to eat a whole apple in the office, it makes so much noise.  Make sure to cut it before you come to the office. 
4. Bring your own slippers to wear everyday. 
5. You need to say when you are leaving the office to everyone, and announce when you have come back into the office. 
6. Do not put your legs on the desk or lean on the desk like you are bored, it looks disrespectful and as if you are bored. 
7. Even if you do have nothing to do, make yourself look busy. 
8. Wear professional clothing everyday, Japanese are very formal. 
9. People do not usually comment on each others clothes or hair cuts, they usually keep to themselves. 
10. Usually people do not talk about their personal lives, unless you are in a one-on-one setting. 
11. Always answer coworkers emails with “otsukaresama desu” (お疲つかれ様さまです).
12. Always have business cards ready at a business meeting and receive a business card with two hands, placing it on the desk during the meeting and putting it in your wallet or a special case.  
13. Make the office coffee with store-bought water instead of tap water. 
14. Be early to meetings and don't be late to work. 
15. Overtime is not expected, especially at the beginning, but will be something that everyone does eventually.

Some of these rules might be a little specific to my company, but overall these are pretty general rules for all offices in Japan. It can be hard to navigate at the beginning but gets easier over time.