Many stories prefer a big city
because it's exciting. But sometimes a story instead needs a small town setting, where people know each other, and "time slows down to a crawl". Of course, size is relative, and a small town can be anywhere from tens of thousands, to a few hundred, depending on your perspective.
A good example in fiction: In The Wheel of Time
series, the heroes come from Emonds Field, which is a small town of a few hundred people. They get to a city (regional capital) and are all amazed at the size: thousands of people! Then they go to the capital city, and discover that "big city" they were so impressed by is considered a small town, and that nobody has even heard of Emonds Field.
There are a lot of specialized subtropes of the small town: