"How bout: Grades are sharp instruments used to slice whole minds into
Oh, alright. Ummmm. . .
Grades are artificial constructs, like scores in sports events, that
do serve a purpose (letting a person know how he or she is doing) but
shouldn't be taken too seriously and are best forgotten during actual
performance. (OK, I don't have a nice tight image for this.)
I don't see the "manageable parts" thing--how do grades partition an
individual mind? Nahh.