As for Paizo being the king of fluff, I definitely agree, but I'll also add that they often go overboard and put in detailed descriptions and backstories that the PCs will never learn about. That does make the modules more interesting for the DM to read, though.
I agree that it makes it more interesting to read, but I've also found that sometimes these things do surface. They also help me structure things better (including deciding how to play NPCs).