A group of people in defined geographic proximity,  with regular contact and some association (e.g. same country, city, workplace, etc)  form cultural norms.   That is behavioral standards for interaction with others.

At any time an individual may belong to overlapping cultures with somewhat integrated standards but the level of detail can vary according to the context of the environment (work,  country).

Cultural Sterotyping

At the country level cultural stereotyping can be quite common.   For example: Canadians are polite, Americans self centered, Germans industrious and so on.

This attributes are not necessarily universal across all the citizens but on the whole the sterotype often defines the behaviorial expectations of people from those countries.

Some interesting  examples I have experienced

As a Canadian in Japan I learned that generally people do not wear shorts in fall and winter months. Even though mid day average tempurature in October can be in the mid twenties degree celcius. This is a dress code that is understood to be the norm even though it is not really comfortable nor logical.

In the work place some companies expect male employees to wear a business suite or a uniform.  This can vary within the company depending on the role.  Except for saftey equipment mandated by law the dress code is just a cultural norm set by the organization. In general,for the purpose of not standing out we follow these cultural norms.

 Follow or be considered strange

Not following the norms can lead to lables such as that person is strange or an exhibitionist.  In reality though often these non conformists are some of the most important contributors to our culturals by keeping them vibrant and alive.