There's an American theory that math problems should be doable, that kids should score 90+% if they're doing well, and that struggle makes people hate things.
That's contradicted in American sports, where coaches push people really hard, boot camps, frat hazing, and cult indoctrination.
There's an Eastern European theory that math problems should be hard, interesting, involve struggle, and often too difficult to solve.
On the whole, Eastern Europeans seem to do better for turning out kids who love math.