Although I’ve argued that basic economics is intuitive, I recommend this short Wikipedia article on the counterintuitive.  Its best example:

[A] policy of catching large fish and throwing back small ones may be
counter-productive. In response to that policy, evolutionary pressure
may select for small fish. A counterintuitive improvement may be to
catch only medium sized fish, leaving the biggest free to breed,
creating evolutionary pressure for fish to grow quickly through the
medium size.