Getting my first C in sixth grade math from this teacher's equivalent when I was in school convinced me grades were a complete fraud and certainly heavily flavored my interactions with school from then on.
In what way? It may be a lot to ask, but I was wondering whether this could be turned into a good thing. Amused contempt is in many ways the right approach to grades - get away from seeing them as a judgement of oneself, and see them as a school game which at certain times will be important to play well, but which fundamentally is far less important than learning stuff.
Amused (with a pinch of self-righteous) contempt, definitely. Perhaps I took from Wargames that the only way to win was to not play the game. It meant in the longer term that I was unwilling to do any work that I did not see directly enhancing or self-confirming my learning in a subject.
I would explain to teachers that "no I would not be turning in my 'class notes' that I would not be taking" or the useless algebra homework. "That's fine, whatever grade you deam appropriate based on that. I am concerned over mastering the material and will only be interested in my test and quiz results." Slightly over-categorized as that competed with my general fear of conflict.
In middle and high school, plenty of Bs in classes that would've been As, but nothing too drastic beyond a few lectures from teachers that I would be unhireable.
It didn't work as well with under-challenging college classes where I would decide a term paper here or there was not relevant to my learning particularly as a requirement from the people I was paying to teach me.
The C wasn't the first straw, and obviously different people in different family contexts, etc. would react different.
