I was a good student, and with a bit of extra credit, I got my share of 105's (out of 100) and 110's here and there. But the best grade that I got wasn't any of those.
It was the D+ that I got on my first report in my senior-year technical writing class. I worked reasonably hard on that report -- not absurdly so; it was just the first report, assigned the first day of class and due within a week. And I'd made good grades in all my previous writing classes, so I thought it was a good solid essay.
I was not unique in this belief; there was much wailing and distress in the class when the grades came back, and I believe the highest grade in the entire class was a C.
Then, after Doctor Robertshaw had given us some time to let it sink in that we -- students who had made it through three years of a difficult engineering program, and had generally made A's and B's in those courses -- had just been handed a paper with a D+ on it, he explained: This was how papers in this class were going to be graded, and by the end of it he expected us to be getting A's on them.
And this is why this grade was the best grade I ever got: Because he was right; that report was probably about 60% of a well-written report. And because it startled me out of my complacency enough to sit up and take notice, and work hard enough to learn how to actually do technical writing well -- which is one of the most valuable skills I learned in my entire undergraduate education.