The complete original question was: "I want to know why there are some differences in culture from American and European since they are both Western countries?"

The first thing I want to point out is that America (or rather, the United States of America) is a country and Europe is a collection of countries (which includes: France, Germany, Spain, Italy and many others). So we are really talking about differences between more than two groups.

If you think about what culture is, the shared values, beliefs and experiences of a group, you can begin to see why America and European countries may have differences in culture. The history (and language) of each of these countries is different and so the shared experiences of the peoples in these countries is also different.

The cultural similarities come from the history and beliefs and values that are shared between these nations. This is what we might think of as Western Culture. The cultural differences come from the unique history and beliefs and values, etc, that each country has had. This is what gives us American, French, German, Spanish, Italian, and other European cultures.

One person is part of many cultures at the same time. As a Canadian I share in both Western Culture and in Canadian culture. I am also part of English Canadian (my language) culture, Western Canadian (my region) culture, Manitoban (my province) culture and Winnipeg (my city) culture. Because of my interests and social groups I am also a part of science fiction fan culture and I am familiar with some musician and juggling culture.

Now think of your own life for a minute. Are you from a rural area or a city? If you are from a rural area you will have a different cultural background than someone from a city. Are you from a rich family or a poor family? Again, these will lead to different cultural experiences. What is your level of education? If you are university educated then you share some culture with other people who are university educated in other countries.

And think of China. People from the north of China have some cultural differences from people in the south of China. Guilin culture is different from Urumqi culture which is different from Beijing culture. But people from all parts of China share aspects of Chinese culture. Each person, no matter where they are from is part of many cultures at once.

And that is why there are different cultures in America and in European countries and yet at the same time they are all part of the wider domain of Western Culture.