In Leslie Ann Moore's, Griffin's Daughter, there are two distinct races that comprise most of the story. Humans and Elves. These two races are very different, but have you really ever thought about how the smallest, most basic aspects of a culture can really define them? In this book I think it really comes down to bathing.
I know that sounds funny, but hear me out. The humans bathe on special occasions while the elves bathe every day. This may seem like a simple matter of hygiene, but really its a view of the world seen at a very small level. The elves manage their day to day lives much like their society, with neat precision. The humans seemed to see each day more like a conquest, stopping to savor the highlights and great accomplishments more than everyday occurrences. It was interesting to see how much small aspects of life can speak of larger world views. And it shows how well Leslie did at developing her cultures and keeping them consistent.