The rules are different. There are laws, the observance of which is strictly obligatory for everyone, and violation is punished. And there are unofficial codes of conduct in society, for deviation from which they are not fined or imprisoned. It is customary to observe them in order to take a worthy place in your environment, to look like a civilized and well-mannered person. Let's talk about why there are rules of etiquette in society.
The word "etiquette" is of French origin and owes its modern meaning to King Louis XIV, who ordered cards to be distributed to courtiers describing how they should behave. Although, of course, in fact, the codes of etiquette have existed since ancient times and have changed at different times and in different historical conditions.
It is worth noting that etiquette is different, depending on what unites a particular circle of people. It can be secular, religious, military, business, professional, restaurant, everyday. The latter can be attributed, for example, to the rule of giving up places in public transport to older people. Not to call on business issues late in the evening and to wear a suit are the rules of business etiquette, in a certain way address a religious priest, properly set the table and choose appliances - a restaurant one.
With the development of new technologies, new types of etiquette have appeared. For example, mobile etiquette, which tacitly defines the rules of decency associated with the use of cell phones. Or the so-called "netiket" - the culture of communication on the world wide web. As with other types of etiquette, their observance is not spelled out in state laws. However, any set of rules has its own system of punishments, and in the case of etiquette, this can be disrespect for others, blocking on an Internet forum or even being fired from work (after all, correct behavior in the workplace is perceived as part of professional suitability).
However, it's time to move on to the previously identified question - why do the rules of etiquette exist in society? In a nutshell, their point is to improve understanding between people. Knowledge of the rules of etiquette allows you to determine how appropriate certain actions are in a particular situation. This can be confirmed by a simple example: when you come to another country, the habits of the locals may differ from yours. If you do what they think is inappropriate in their presence, they will not like you. But if you remember their rules of behavior and will reckon with them, you will quickly find a common language with them and become your own.