When I think of a coffee shop, I don't think of gourmet coffee. Coffee houses, on the other hand, are for those who desire gourmet coffee.
A coffee shop is a little piece of heaven. It's a restaurant open 24 hours on the weekend and nearly 24 hours on weekdays in which you can get breakfast, lunch and dinner at all times. Their menus tend to be extensive and they are the providers of "comfort food". In New York, they tend to be owned by Greek families. They also offer terrific value for the dollars spent. Some might call coffee shops "diners".