I also think economics is just not intuitive for a lot of people, even smart people.

For example, an engineer friend of mine asked me why I would take out a car loan at 0% interest for the first year if I was able to pay it outright. He didn't have in mind the opportunity cost of capital because he's never thought about it. (This is when we were both in our early 20s, so before he's had a chance to manage any real money.)