Privacy in U.S.

Before I came here, I've studied about American Culture in University. That was why I know a little bit about it. But when I'm here, I know some more things. And one of them is that there are a lot of differences between U.S. and Vietnam about privacy.
First of all, there are many family members live in a same roof, so there is not enough room for everybody. Unlike that, almost everybody has their own room here and no one can come in without their permission even they are the small kids. In my opinion, it is better because every body has their own right to keep privacy.
Another one is that when they are eighteen, they would like to move away from their home. They want to live independently. In some cases, some one cannot do that.When his/her friends ask them where they live, it's a little bit weird when they say they still live with their parents. However, Vietnamese would like to live with our parents than live by ourselves. When we get married, we live in our own house. Our houses are often near our parents' one.
There are a lot of things different from here and my country. However, I will follow some new culture and also keep our own one. I think it is better than just keep the old one or forget them and just follow the new one.