A mistake is a fault; thus, it would be wrong to give someone 100%.
The school system is far too easy as it is, so it seems strange that one would complain. Was I an "A" student through and through? smurf no, I didn't do




in the classes that didn't interest me. But for the classes that I paid half a thought to, I achieved A's rather easily.
Achieving 60% is simple, and honestly, I am amazed that you would complain about it knowing that you didn't place any effort in the class.
You reap what you sow.