US schools definitely mess with your head the higher of an achiever you are.

In remedial classes, in most places, 60 is passing.
In normal classes, in most places, 70 is passing.
In advanced classes, you may be kicked out for scoring under 80.

The intuitive concept of "barely good enough" keeps getting higher as you perform better, plus of course each of these types of classes are progressively more difficult by their nature. It really fucks with people who are excellent in some subjects but average in others.