I remember one paper I had in high school. I worked hard on it because it was a subject I enjoyed greatly. (The Origins of Middle Earth: Fact and Fiction. The first half was where Tolkien got his ideas and the second was, mostly from the recently (then) released Silmarillion, on the mythology of the actual world.) I was so interested in the research that I was still writing the paper the period before it was due and I handed it in without the benefit of proof reading. Or the sorely needed spell check because I can’t spell worth a darn and computers were still the things of NASA and science fiction.
I got it back with only the first page corrected, mostly spelling mistakes, and a grade of 110. My professor got so interested in reading the paper, he forgot to grade it! That was the only time I actually felt I deserved “extra credit”.