I live on a world where people think that the Earth is flat and either have never heard that the Earth is round or don't think it's true. In either case they don't understand the implications of a round Earth--that a flat Earth extends outward forever while a round Earth is measurably finite.
Runs parallel to the truth of
I live on a world where people haven't heard or don't understand that oil production rates over time follow a bell-shaped curve. This is just as simple as a round Earth. They don't understand the implications of being on the downward side of the oil production rate curve either--that there is right now a shrinking supply rather than an abrupt cut-off. It's like a global game of musical chairs.

