Cultures are complex
Any culture is complex; an outsider will rarely be able to understand it without living in it. Another potential problem is that cultures are changing all the time. Sometimes even people living within a culture are not fully aware of the changes as they are happening, or they may be actively resisting them.
If you have been living in New Zealand for several years, you might think about how the range of foods considered 'normal' has changed dramatically in the last twenty years.
See Culture as an iceberg for some of the 'unseen' aspects of cultures.
The Interview: an example of cross-cultural communication confusion.