Some people at a university operated a "bank" of term papers and other homework assignments where students could buy ready-made work. There were papers to suit all needs. The "bank" had A grade, B grade, and C grade papers, since it would be rather suspicious if an undistinguished student suddenly handed in a brilliant essay.
A student, who had spent the weekend on pursuits other than his assignment, went to the "bank" and purchased a paper with an inconspicuous C grade. He then retyped it and handed in the work to his professor. Soon, the student received the paper back with the professor's comments, which read, "I wrote this paper myself 25 years ago and I always thought it should have been graded an A, so now I'm more than pleased to give it one!"