It is not a myth, Japanese people are very quiet, and not only in public places but in their own apartment too, and houses insulation is not the best we could find, in "Apa-to" as in "Mansion".
I have never seen such quiet people! I often have the feeling that there is no one in the apartment next to mine, until I heard a small sound that makes me remember that walls are very thin. And it also reminds me how noisy I am probably for my neighbors..
I understood it few months ago.
When my neighbor moved in, he arrives with his family to move all his furniture in. They were speaking together, and I could hear everything. Not until understanding all conversation but still heard them quite clearly. Noises don’t bother me (except of course in the middle of the night). In fact I personally prefer to hear that there is life around.
So my neighbor continues to move in and discuss with his family. It continues until the evening, when I received a call from my family. I was speaking in the phone, so I guess my neighbor heard it, and understood that we could hear everything in next apartment.
From this day, I have never heard him anymore.
I often think that there is no one in the next room, until I heard him sneeze. This is the only sound I hear from him, an it reminds me that yes, there is someone, but soooo quiet.
I know that I am not considered as a noisy person in my country, but here in Japan, I probably am. I am doing my best to try to do not walk noisily, laugh or speak loudly when I have calls or skype with family and friends. But when you speak in your own language, you don’t realize that volume is going up very fast. I feel so sorry for my neighbor, and I hope he is alright with it.
Because here is a big problem I understood by working in a real estate company.
When neighbors are noisy, Japanese people don’t tell them directly. They don’t ask them, don’t knock on the door or on the wall to make the noisy person understand it is too loud, don’t write a note of something. They won’t inform or tell anything to their neighbors. However, they will directly complain to the management company of the building.
The management company will send a letter or call the noisy tenant, and when it is a foreigner, the person is always very surprised and doesn’t understand why his neighbor didn’t complained to him directly.
If noise doesn’t stop, it could go far, the management company could ask the tenant to move out.
So for foreigners who live in Japan, please be careful even when you are alone at home! And if you want to meet some friends, it is better to do it outside, like japanese people do.