Defense of Poesy

What the Dickens was going through the addled mind of top-rhymster William Wordsworth when he settled himself down in a comfy armchair, took up his trusty pen and decided that what the world needed most was a poem entitled "To the Spade of a Friend"? I can fully understand William Topaz McGonagall wanting to extol the virtues of Beecham's Pills. I can forgive the well-intentioned sentiments that resulted in A Tragedy by Theophilus Marzials. Julia A Moore (The Sweet Singer of Michigan) probably, at one time or another, had second thoughts, one of them being, "Hmmm, not quite up to snuff this time, Julia." Samuel Pepys thought the poetry of Margaret Cavendish, Duchess of Newcastle, was "the most ridiculous thing that ever was wrote", and she doubtless had niggling doubts about some of her latest lines once in a while. But a poem to a shovel? And what was on Mr Burns' mind here?