And we GPs could sing a few bars of that: I once defibbed an old chap, not a patient of mine, and two weeks later he passed me in the street and didn't give me the time of day. The converse is also true: sometimes patients are grateful when in truth we have royally screwed up and escaped by the skin of our teeth.
The ingratitude of patients is nothing new. Last year, I visited WB Yeats' grave and sat awhile in thought: no towers of adamant nor rings of steel, just a simple stone monument with the words: 'Cast a cold eye/On life, on death/Horseman pass by.'
A few hours later and a few miles south, I was in a bar on the Atlantic coast, drinking a pint of the blackest porter, eating crab claws fresh from the sea and soaked in garlic butter. Pausing to check that the kids were still alive (exposure to bitter north-west gales and 12-foot waves being an essential ingredient of the magic of childhood) I fell into conversation with a local, who, on the ubiquitous subject of famous literary graves, told me proudly that Dr Oliver St John Gogarty was buried nearby.
Gogarty was unflatteringly immortalised as 'stately, plump Buck Mulligan' in James Joyce's Ulysses, but he was a substantial literary figure in his own right, and like most of us substantial literary figures he needed the day job to make a buck; further evidence of how the vocations of medicine and literature constitute a fecund union.
It was he who performed the autopsy on Michael Collins, Ireland's lost leader, assassinated at Beal na Blath in County Cork in 1922.
Gogarty died in America; his body was flown home in a lead-lined coffin and he was buried in a graveyard overlooking the ocean, with all the honours a grateful nation could bestow. And a few weeks later the natives dug him up and sold the lead.