Completely agree on this. Something I have used for a few applications is the DMA (designated market area) boundaries. It's not ideal for everything, but it's very human-focused: If you live just a few miles across a state boundary from a major city, grouping you with the city makes more sense than with anything in your state.

In fact, these were invented by Nielsen, and they determined them just by measuring which city's TV stations are predominantly watched in each county, and assigning each county to one DMA based on that.