What unspoken rules should everyone respect?

I'm writing here 50 rules that everyone should know and should follow. It's the life that taught me.

1. Always say thank you, when it's needed.
2. Never break a promise. When you swear something, when you promise it, do everything to keep your word.
3. Wearing headphones in public is a code to say "do not talk to me". So if someone is wearing it, do not talk to him.
4. Always be nice, especially to those who bring you food.
5. In all the negotiations that you do (in family, between friend and especially in business), do it in writing. Sign a contract.
6. When you meet someone, be sure to have a firm handshake.
7. When someone walks his dog and approaches you, ask permission before stroking the animal.
8. Do not flatter proudly, let alone around people.
9. Do not play with your phone when you are around people or in a public place.
10. When you post something vulgar or insult someone on the Internet, it says more about you than the person you insult.
11. If you have borrowed something, make it right after using it.
12. Everyone needs a personal space, a moment of their own.
13. Prefer the phone call rather than messages during a formal discussion.
14. Be quiet when other people are sleeping. This means not to talk, not to slam the doors, close the drawers with caution, etc etc
15. Put things back in their place - both at home and at the store.
16. If you are finishing the toilet paper at work or at home, be sure to bring another roll of PQ or be sure that people know that there is no more.
17. Have a healthy lifestyle (be clean)
18. Always hold the door for the elderly - your parents including
19. Do not sneeze and cough in the direction of people, neither in your hand, but in your elbow
20. Do not raise your voice when you talk to your parents and do not be vulgar with them.
21. You will not comment on the baby making noise in the movies. At the limit, you will see security.
22. When you go to someone's home, never look at their computer, their room, their drawers or their fridge without their permission.
23. When you know someone for a long time, as long as they do not try to talk about it themselves, never ask them about their age or salary.
24. Do not embarrass your host by asking him something he probably does not have.
25. When you wait for a visit, make arrangements to make them feel welcome.
26. When someone brings you to the restaurant, always wait for that person to order first. Look at the price of the dish he picks and line up.
27. Do not let your guests set the table, unless they insist.
28. Never hit anyone. But if things go wrong and he starts to hit you, try not to take the first shots. And replicate, loudly.
29. If you are parents and the friends of your children come home: For dinner, do not sit with them. They will not ask for food if you are there.
30. Do not judge people by the way they dress or because of their religion (obvious huh)
31. Living with your parents is not ok, live in your own home when you grow up (especially in the US)
32. Do not ask about someone else's religion, about their political opinions, unless they are open to talking about it.
33. When you have to pay at the cash desk, pay with change when it comes to a small purchase (a few cents or euros) and not with the credit card.
34. You can not blame society for your failures.
35. Always answer people you know and your friends. If you see the message, answer, make the habit. Otherwise, put the phone away to not see the message :)
36. Each office will have people with different nationalities. If you eat all together, do not speak in your native language.
37. Do not look at others' toilets, it's uncomfortable, irritating and boring.
38. In public transport, listen to music in your headphones. (Initially, I did not understand this advice - But after several indications by readers, it would be not to listen to his music on a speaker but rather on headphones, not to disturb)
39. If you call in a public place, always speak quietly and calmly so as not to disturb people around you.
40. Do not smoke while walking. It's painful for people behind.
41. If you have to turn right, make sure to be in the right lane - no "I pass from left to right directly by cutting the road to people behind"
42. The highway code is important. Follow the rules of the road and traffic lights.
43. Listen, always watch and always be ready to improve the situation.
44. Avoid staying in someone's home for more than three days. No matter how close you are to this person, you change their everyday life and their personal lives.
45. Have confidence in your life. It will be a blessing of the gods during hard times, urgency, depression or hardship.
46. If you borrow a car, return it with full fuel if necessary.
47. Wish the cashier a good day. A smile will not cost you anything.
48. Consider the very people who are below you (hierarchically or otherwise). In short, be humble and modest.
49. Do not judge people by their gender. Everyone has the same rights, and can live as he sees fit.
50. Women are not sexual objects. Treat women as human beings.