"You know the Model of your Car. You know just what its powers are. You treat it with a deal of care, Nor tax it more than it will bear. But as to self — that's different. Your mechanism may be bent, Your carbureter gone to grass, Your engine just a rusty mass. Your wheels may wobble and your cogs Be handed over to the dogs, And on you skip, and skid, and slide, Without a thought of things inside. What fools indeed we mortals are To lavish care upon a Car, With ne'er a bit of time to see About our own machinery!"
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Source : John Kendrick Bangs (1920). “The Cheery Way: A Bit of Verse for Every Day”