In the United States when people meet each other from the first time, they talk about things like family, work, school, or sports. They ask question like :
- Do you have any brothers or sisters ?
- Where do you work ?
- What school do you go to ?
- Do you like sports ?
- Where do you come from ?
- Where do you live ?
These are polite questions. They are not personal or private. But somethings are personal and private, and questions about them are impolite. People don't ask questions such as :
- How much is your salary ?
- How much did you pay for your watch ?
- Why are single ?
- Why don't you have any children ?
- How old are you ?
Such questions are considered impolite. It is also impolite to ask people questions about politics or religion unless you know them.