many students, once tasting the sweet fruit of being better than their peers at something, identify with that success, and strive to continue "being the best" (in general, or at a specific subject)
it becomes their identity, and their primary motivator
"I am a good student, therefore, I must strive to have good grades (better than most others), so that I remain a good student"
(or, for a specific subject: "I am good at math, therefore...")
BUT, this comes at the expense of other students (a "good student" can't be better or best, without others to be better than), who then identify with being a "bad student" (or "bad" at a subject)
~ "I can't win at this game, I'm not good at this game, so the game isn't worth playing"
how many "bad students", who gave up on a subject (or learning in general), had it in them, but had a negative experience because
of course, this "ranking" and "comparing against others to determine self-worth" are terrible mindsets, and should be avoided, but they are very real
in the abstract, one could ask:
is it worth it? would we be willing to prop up a "good student's" ego, at the cost of other students?
the way grading is done contributes to this, makes it easy for students to compare
it's partly why I'm a stronger supporter of pass/fail and mastery based learning
the only thing that's left to compare on is velocity (speed of progress within a subject, or overall), but that seems less prone to identity formation
"growth mindset" and "continuous effort", and "self-progress, without comparing to others" are all much better mindsets and less fragile