Another interesting window in this vein is the local courthouse. The smaller towns don't separate out traffic violations from everything else, it's all on display handled in one room. You can get a sense of what's going on and the type of people in a given small town rather quickly this way.
When there's just one grocer serving a given area, it's effectively the same situation. But when competition eventually arrives, I think they tend to quickly divide along class boundaries.
Around here there's only one grocery store in my local town, and as a result it's actually pretty decent. The exact same chain has a very similar store in a significantly larger town ~25 miles away, where there's a competing upper-class grocer in the adjacent lot. The effect is devastating on the mediocre chain. Customers are treated poorly, the place is a filthy mess, cashiers aren't even trusted enough to manually enter prices when a barcode won't scan. The contrast is shocking, just next door in the higher end grocer none of these problems are experienced, but the prices are slightly higher.