Today in the Superbowl for us in America, and since my family is in a celebratory mood (to watch the ads), I will keep this brief. Today got me thinking about how important traditions are for every society. In modern America, we have things like Superbowl and Black Friday. Even older traditions like Christmas have become very specific to this generation (for example, the shopping rush around Christmas and lack of religious undertones of the holiday have only been around for less than a century).
Traditions are something important to a society, but are largely forgotten when it comes to writing fiction books, especially those set in history or a completely fantasy world. In developing a world or researching a historical era, make sure to spend time understanding traditions.
Writing a book set in 19th century Korea, I am learning this is an all important tip, since Koreans back then (and even now) had so many traditions that the western world is not familiar with or would not be able to relate to.
So research traditions, whether our own or in ancient times. Or create your own for a fantasy book. But understand the importance of tradition in every society and, even if we dismiss them as pointless, there is usually a lot of importance in them.