Here's a misconception about US healthcare... foreigners think that you have insurance and it covers everything. That is actually far from the case. They'll deny for random reasons and make you jump through hoops to get procedures. Then you have to make sure your provider is in your network (and how difficult that is varies depending on provider), because if not, guess what? You pay double or more! If you go to the wrong urgent care, same thing. Go to the wrong ER and if the ER doesn't term it correctly, you might get the whole thing denied. And heaven forbid you get an ambulance or life flight... those are almost never covered, even if it is medically necessary to survive.
These little details of how coverage works are, in my opinion, the worst part of the US system. Worse than the costs, worse than the shitty rural doctors, worse than gotcha charges... the fact that you have to prepare for each and every instance of using it, including emergencies. If every hospital, doctor, nurse, ambulance, etc was forced in-network and it was a simple pay ___, have ___ out of pocket max, and you get coverage anywhere... I think there would be far less complaints about the US system. It would at least be transparent that way. Instead we have the similar waits, gotchas, fights, and we pay high amounts.
Three weird examples:
Right now I'm fighting with my insurance on getting a plate removed in my elbow. It was done as an emergency surgery, so wasn't the perfect operation. The plate rubs on a ligament hurting mobility, causing long-term damage that will eventually have to be repaired, and occasionally causes bursitis. These issues want me to have it removed. Yet despite 3 doctors agreeing it is medically necessary, my insurance won't allow a surgery to remove the plate. My options are basically pay 7500 for the procedure or live with it until the ligament fails and then insurance will cover it.
Another is my wife has a rare situation. She has early onset menopause where she is 36 and basically has no estrogen (and an number of other hormones). This causes all sort of issues longer term from elevated risk of stroke to osteoporosis. It is very well documented that estrogen and other hormone replacement therapies basically solve the long-term health consequences. Yet because she is under 40 and having this issue... insurance won't cover any hormone replacement costs. We have to pay out of pocket for these. Luckily we are well enough off we can afford the 1k bill every three months for the next few years until insurance will cover. But even after that, they will only cover estrogen up to a certain dosage. All the other hormones are not covered, nor is estrogen to get to normal levels, just to the bare minimum. Odds are high we will still have a ~5-600 bill in a few years instead of a thousand.
The last one... one of my friends got himself in a pickle. He loved an unclean woman, developed an infection, and then had a reaction to an antibiotic. It was a pretty serious case (SJS) and it a fairly life or death situation (he actually went into sepsis at one point during treatment and almost died). Instead of calling for an ambulance to the ER when he was really ill, he called an Uber (because that ambulance was OON). Then the hospital he went to couldn't treat him. So they had to get him to a different hospital pretty quickly. Luckily it was only ~40 miles away so he could go via ambulance (a different provider that was in network) instead of a life flight. But adding to this, his stay in the burn ward... the only way to stay alive mind you, was out of network and was initially denied. He had to sue to get it covered. He dealt with that situation for almost 2 years after the issue, and he's lucky that his dad is a doctor and well off... otherwise he might have been stuck with the bill to save his life. Which was high 6 figures.