You ever see a dog that’s got its leash tangled the long way round a table leg, and it just cannot grasp what the problem is or how to fix it? It can see all the components laid out in front of it, but it’s never going to make the connection.
Obviously some dog breeds are smarter than others, ditto individual dogs - but you get the concept.
Is there an equivalent for humans? What ridiculously simple concept would have aliens facetentacling as they see us stumble around and utterly fail to reason about it?
Unintended consequences. People like to propose grand schemes that will “fix everything”, but refuse to accept that there are downsides to that grand scheme.
Oh boy, that’s going to offend all the communists.
In the same vein, refusing to consider something that will have a small positive effect, or a partial solution, because it won’t fix everything.