Keep in mind that instead of measuring overall interest in a topic, Google Trends shows users' propensity to search for that topic on Google on a relative basis. For example, just because a particular region isn't on the Top Regions list for the term "haircut" doesn't necessarily mean that people there have decided to stage a mass rebellion against society's conventions. It could be that people in that region might not use Google to find a barber, use a different term when doing their searches, or simply search for so many other topics unrelated to haircuts that searches for "haircut" make up a very small portion of the search volume from that region when compared to other regions.