People are complex
Culture is only one factor that influences how people think and act. People's personalities and their own experiences are also influential. Think about an aspect of a cultural group that you belong to but which you don't follow (for example, you may be a New Zealander who is not in the least bit interested in any kind of sports).
Any person is the member of several cultures at the same time (e.g., an ethnic group and a gender group and an age group). Sub-groups may have different beliefs and customs (e.g., Pākehā men traditionally have had a different role as parents than Pākehā women). These beliefs and customs may even be contradictory (e.g., for a student in a NZ university whose ethnic culture expects primary loyalty to meeting family needs while the educational culture expects adherence to due dates).
A person may be bi- or even multi-cultural, that is, recognised as fully competent in two or more cultures within the same category (e.g., was brought up as a Catholic and has joined a Buddhist community) - it is not always obvious which culture is influencing their conduct in a particular instance.
- there is not agreement by all members of the group, for reasons listed below
- and because People are complex
- changing all the time
- sub-cultures emerge when there is a large enough group within the culture that differ from the others on some, but not most, features
- the fundamental parts of a culture are hard to see. See Iceberg example.
- factors other than culture influence behaviour e.g., personalities, experiences, power in society
- they belong to more than one culture
- they may have modified their behaviour to respect your culture