The ceramics teacher announced on opening day that he was dividing the class into two groups. All those on the left side of the studio, he said, would be graded solely on the quantity of work they produced, all those on the right solely on its quality. His procedure was simple: on the final day of class he would bring in his bathroom scales and weigh the work of the "quantity" group: fifty pound of pots rated an "A", forty pounds a "B", and so on. Those being graded on "quality", however, needed to produce only one pot - albeit a perfect one - to get an "A".
Well, came grading time and a curious fact emerged: the works of highest quality were all produced by the group being graded for quantity. It seems that while the "quantity" group was busily churning out piles of work - and learning from their mistakes - the "quality" group had sat theorizing about perfection, and in the end had little more to show for their efforts than grandiose theories and a pile of dead clay.
For some reason it just seems we in particular could learn something from this anecdote.
Iterate more. The practice effect is your friend as is mining out positive outliers in really huge sets. I wanted to also mention something about using going meta as a way to procrastinate but I feared I would summon a Newsome.
Edit: This has been mentioned before. I think it is good to remind people of it.
Not only has it been mentioned before, last time it came up I searched and failed to find corroboration of the claim that it actually happened. Since applying a deliberately inconsistent grading rubric is not something professors are normally allowed to do, I strongly suspect that the anecdote is fictional.
It is therefore best to assume this is a parable.