Culture plays into it too. For example here in Finland, school grades are from 4 (failed) to 10, and that ends up skewing how you see any scale from 1 to 10.
As a bit of trivia, originally there were grades lower than 4, but at some point it was decided it wasn't necessary to determine just how badly you failed. Knowing that you did should be enough. So all the failing grades were bundled up into one, which ended up being the previously highest failing grade.
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.
Percentage of points. So if you get half of the questions wrong on a test, you fail. In some cases, teachers will grade “on a curve”, meaning they normalize the class scores. My organic chem teacher in college liked to make extremely difficult tests, so you’d get 40% or something awful like that and it would turn out that nobody in the class scored over 50% so you actually got an A.