A boundary defines what is inside and what is outside of a category. A culture and its needs sets the importance of one thing to another, or its relative importance.
One person may not be all that interested in sports, for example. Knowing someone is a football player or a hockey player may be all he needs to or cares to know about the subject.
For another person, they would be interested in knowing not only if the person played football, but if he played offense or defense. If defense lineman, linebacker or secondary. If secondary, safety or corner. If safety, free safety or strong safety.
One person's football player is another's strong safety.
Cultures are the same way. Vocabulary and categories of things experienced in normal life depend on the environment and culture. Eskimos need to know different names for snow, Hawaiian islanders not so much.