When I was a kid, one of my greatest joys was having my current best friend over to my house for overnight stays on the weekends or for several days during the summer. Good friends are like candy when you're a kid. You can never have too much.
While a friend was staying over at my house, my parents generally ignored their presence and went about their business as usual. They didn't feel they had to be overly solicitous or accommodating. They only felt the need on occasion to tell us to shut up and go to bed when giggling or talking carried on late into the night.
A few days ago, I was conducting a lesson with a student and one of the questions was about whether or not the student would like to be famous. She said she would like to be famous because her extended family (cousins, aunts, uncles, etc.) would have more contact with her all the time. When I asked her why they did not have much contact with her now, she said that they lived too far away. She said she liked hanging out with her cousins and talking with them for long periods of time when she was younger and they lived closer and said she envied me because I grew up living near 8 of my cousins (whereas she only has 2). For the record, my student is a friendly, happy, charming young woman and there's no way her family avoids her because of her personality.
Since most young westerners are generally less attached to their family than their friends, I asked her why her university friends weren't sufficient to keep her company. She said that it was very difficult having them over or going to her friends' houses because their fathers came home from work tired and couldn't relax around a visitor. I asked if she ever had her friends stay overnight with her when she was younger and she said that she never had. When I asked her why she felt friends rarely stayed overnight in Japan, she said she thought it was because houses were too small for the parents to have any real privacy when guests visited. She could have her cousins over without putting her parents out because they felt comfortable being themselves around family.
I didn't discuss this point with my student but I wondered if part of the reason parents couldn't fully relax around their children's friends is that Japanese culture is generally more concerned with what others think than American culture. My Dad might have felt perfectly fine in his casual clothes, watching television and drinking a beer while ignoring my friends but a Japanese father may be somewhat concerned with how his actions may be viewed and mentioned to the parents of a child staying over with his child.
I felt rather bad for my student because she never experienced the giddy joy of carrying on with a friend in an extended and relaxed fashion. That sort of camaraderie and bonding doesn't come as easily in public spaces or in small spans of time.