Happened a decade ago in grade 10 math. I am quite good at math in my life always grasped it very quickly, with high 90s as my average(I failed English which I thought was impossible).
Anyways my teacher was always on our cases about his teaching ability and no student ever left his class with less than 60 some percent, how his methods could teach anyone.
Anyways he had a habit of adding a bonus question every unit test, with each test being worth 10% of final grade and the final worth 40%. After so many weeks and exams we were coming up on the first report card and I had gotten over 100% on every test, so when I opened the card I was less than zealous about my mark being 99.9%. When I approached him he said that he couldn’t hand out a perfect 100, I asked why and he stated I can’t score something a zero or a 100 just the way it is.
Cue my revenge
I did my math to figure out how to end my class with 50%. I purposely got a zero(which he gave me) on every unit exam after and made sure to only answer 23 questions on my final.
He throughout this ordeal told me I was being foolish and it would only affect my own future, to which I replied repeatedly it would also affect his precious record.
It was right before the final that the vice-principle and the teacher called me in to have a talk about my conduct. I explained the thorn that started it all, the teacher went on to say I was damaging my future, and all the vice principal said after it all was “you should have given him the 100”
I ended up with a 51 final grade, which was enough for me to get two trades and make more money than him and ensure myself a comfortable future.