“Sweet are the uses of adversity, which like the toad, ugly and venomous, wears yet a precious jewel in its head.”—Shakespeare 

You can learn a lot from watching muscle fiber.  Throughout the day you'd see it subjected to all sorts of friction, trauma, and the depletion of its natural resources.  But if you stuck around long enough, you'd see the same end result that you're sure to realize as a result of the test and trials you've undergone lately . . . NEW GROWTH!