How to behave in a museum? [closed]

While travelling, specially in cities, it is common to visit museums. Since tourists come from a lot of countries, you encounter other ways of approaching the museum and the experience.

However, it is also common in this places to be crowded and there is a "competition" for the best space or the best angle while taking pictures.

What kind of courtesy can you expect when visiting a museum? Do you have to adopt your own country courtesy to the one from the country you are visiting? And what about visiting country A being you from country B and other people from country C?

For example: if you are used to silent museums, are you entitled to ask people to speak low or you should just give up if the museum workers do not do it?

Yet another example: if you see people touring in the rooms on a different direction as the flow, are you entitled to ask the people to be careful? Also if kids are crying very loud and parents do not care, etc.

So the general question here is: what kind of politeness is supposed to cover a "museum experience"?