There are diverse cultures in real life and in numerous imaginary realms. Culture can be so clear and obvious or it can be subtle. It can have so many components or only a few.
Sometimes I write about the real world and when I do, I try to develop and share some understanding of at least one culture. The same holds true for fictional cultures.
Like most writers, I enjoy playing goddess. The irony is of course, that when writing one learns even more about how some events lead to others in an inexorable manner. We learn about that in real life as well, through our experience with actions and consequences. Even so, as an authoress I have found that I don’t always see events coming with rough drafts.
That granted, I do enjoy devising cultures. I know that for readers it may seem as bizarre as it is in practice, to have some aspects of a story conform so well to my plans while others grow from the decisions that characters make as the plot moves along.