Embers actually has my favorite example of it-- the Avatar fanfic author has read a lot of Japanese stories, and other mythology, but knows a lot of people haven't; so occasionally her characters will complain about this or that being "just like a spirit tale." (especially in the Fire Nation, which she's having had go through the "rational" part of an industrial revolution to match their ships and other tech; other nations will more often complain that this and that only happens in spirit tales, or is nothing at all like a spirit tale.)

Came to mind because a little thought-bubble popped up that you could do some very fun world-building by what they talk about as stories; I hadn't even considered how much of the "tone" of the various cultures I'd picked up from the chatting until then.