What is the big deal?

After reading all of the postings, I still do not understand why author wants to go to court. What is the big deal between B and B+ ?

I once reported a score error to my teacher and he corrected it from B to B+. But in the school assembly, the president said some students liked to seek higher scores, but I would like to seek high quality to accomplish the assignment, high ability to do the practical work, and high achievement in future. Score is just a number, please pay more attention to the quality work.

What a shame to me at that moment!