Yeah, I know every setting has regions with geological or cultural tropes. But in Golarion, each region also has unique mood, tone, theme and even genre AND each region is specifically more self contained and autonomous of every other region than any other setting in familiar with. There's very little connective tissue between even neighboring regions other than, like, the Pathfinder Society. Each region has its own iconic villains and challenges, A River Kingdoms campaign vs a Galt campaign won't have, say, the equivalent of the Red Wizards of Thay as go-to villains. Golarion more than any other setting I've looked at is one where you don't set your game in Golarion, you set it in Cheliax or Varisia or whatever, and the region acts, for all intents and purposes like the entirety of the setting during that game.
