Re-calculating an average is pretty straightforward - something above the average raises it, something below it brings it down.
With each new score on a test it’s easy to calculate the effect on the average (and to see how you compare), but with something more abstract like a day, the effect can seem a lot more difficult to work out.
But it’s not.
The odd below-average day won’t make that much difference over a whole life, but putting in the thought and effort to at least try to make each day better than the last ? There’s only one way that average is going, and it sure as heck isn’t down…