Abraham Lincoln:

It is said an Eastern monarch once charged his wise men to invent him a sentence, to be ever in view, and which should be true and appropriate in all times and situations. They presented him the words: "And this, too, shall pass away." How much it expresses! How chastening in the hour of pride! How consoling in the depths of affliction!

This clip does for me what that sentence did for the Eastern king...

Jumping the shark is my "this, too, shall pass."