Things that are so obvious and ingrained that no one even thinks about them.
Here’s a few:
All US americans can go to Mexico EASILY. You’re supposed to have a passport but you don’t even need one (for car/foot crossing). Versus, it’s really hard for Mexicans, who aren’t wealthy, to secure a VISA to enter the US. I’m sure there are corollaries in other geo-regions.
Another one is wealthy countries having access to vaccines far ahead of “poor” countries.
In US, we might pay lip service to equal child-hood education but most of the funding pulls from local taxes so some kids might receive ~$10000 in spending while another receives $2000. I’m not looking it up at the moment, but I’m SURE there are strong racial stratas.
Makes you wonder if our success as a nation had more to do with explosive growth, immigration, and opportunity. Or maybe the system worked well under those conditions, but now the whole environment is steady state and it doesn't work quite as well.