Looking at the Guardian online I learn that today is National Poetry Day. Good timing on my part, though I'm of the opinion that if you have to impose a day of celebration for something on the populace the cause is already lost.
This one's by Robert Graves, who claimed that it's from the Welsh. I wish I could find the original, not that I would be able to read it -

TRAVELLER'S CURSE AFTER MISDIRECTION

May they stumble, stage by stage
On an endless Pilgrimage,
Dawn and dusk, mile after mile
At each and every step a stile;
At each and every step withal
May they catch their feet and fall;
At each and every fall they take
May a bone within them break,
And may the bone that breaks within
Not be for variations sake
Now rib, now thigh, now arm, now shin
but always, without fail, the NECK.

I do love a good cursing poem, "The Curse of Doneraile" is a good example, although literary folks might look down their noses at it. The curse was laid upon the town by a priest who had his watch stolen there. When the watch was recovered the curse was lifted, again in verse. A similar curse was laid by the poet Ian Duhig on the gouger who nicked his fountain pen.
I also like a dose of invective in verse, useful for expanding one's vocabulary of insults. Apollinaire's Cossacks' reply to the Ottoman Sultan is particularly scabrous -

Poisson pourri de Salonique
Long collier des sommeils affreux
D'yeux arrachés à coup de pique
Ta mère fit un pet foireux
Et tu naquis de sa colique
(etc.)