We are indoctrinated to believe that "the US is the greatest country in the world" from a young age but what is this based on?

Whenever I hear how great the US is it gets me fired up because we can and should do MUCH better. What's the metric that makes us so great? In the US approximately 21% of Americans are illiterate.

https://www.thenationalliteracyinstitute.com/post/literacy-statistics-2024-2025-where-we-are-now

Another 30% cannot do basic math.

https://www.wyliecomm.com/2021/11/whats-the-latest-u-s-numeracy-rate/

We have the worst outcomes in healthcare by nearly all measured metrics and the most expensive care in the world.

https://www.ajmc.com/view/us-health-care-system-ranks-last-overall-among-other-high-income-countries