Practical jokes simply are not funny when they they visit betrayal and humiliation upon another person.
A lesson in cruelty after a royal prank turns into a tragedy
An announcement of a royal birth is always guaranteed to send the public pulse racing in the UK and, true to form, the newspapers have been full of the Duchess of Cambridge's pregnancy after the news broke last weekend. Yet this simple story has developed in a way that none could have predicted.
The Duchess had been admitted to the exclusive King Edward VII hospital in the centre of London after suffering acute morning sickness. The hospital is no stranger to handling VIPs, but it only takes a moment of inattention for security to be breached.
Thus it was that an unsuspecting nurse who answered the telephone was persuaded that an incoming call was from Queen Elizabeth and Prince Charles requesting an update on the Duchess's condition.
In fact, it was a publicity stunt by a couple of chancers, Mel Greig and Michael Christian, for a show on the Sydney-based radio station 2Day FM. The unsuspecting nurse, Jacintha Saldanha, forwarded the call to a colleague on the ward, who gave a frank summation of the patient's health to the gleeful radio presenters.
No matter that the impersonations was remarkably tactless - the prank rendered the unoffending nurse something of a laughing stock in the international media.
But never mind. No harm done. Or so it seemed. The Duchess was safely discharged a day later, we all had a good giggle, and life moved on. The only person affected was Ms Saldanha, whose unblemished four-year record at the hospital was now tarnished, albeit through no fault of her own.
Then the news turned tragic - Ms Saldanha was found dead on Friday morning. It's too early to speculate on the cause of her death, but suffice it to say that her last week must have been difficult. Hospital spokespeople confirmed that Ms Saldanha had been going through a bad time in the days since the hoax. She leaves a partner and two children.
I've always found baffling the nature of practical jokes and pranks - and indeed, those who purvey them. It seems that those who indulge in such pranks are themselves trying to replicate a sense of humour they don't actually possess, much like the cafe bore who substitutes an endless stream of jokes to cover his lack of wit.
Radio shock-jocks are particularly susceptible in this regard (with several high-profile examples in the UK in recent years), while even in the theatre I know a number of actors who are notorious for playing pranks during performances. It's a dreary indulgence that forces their colleagues to pretend to find it funny to avoid causing offence. What could be less amusing?
My parents ran a little store in Britain while I was growing up, and on one occasion they were persuaded by a particularly glib salesman to install a small stand devoted to such diversions: sachets of itching powder, fake sugar cubes dotted with plastic flies, plastic dog mess that you could place in the middle of the carpet. Very classy stuff.
One incident changed my attitude forever. One of the products was a set of stickers with cheeky sayings on them, one example being "notice my beautiful body". One night I decided it might be a laugh if I stuck the label on my mum's back while she was serving customers in the shop.
It did indeed raise several smiles. But my mum was by then in her mid-50s, a large woman who despite her amiable personality was struggling desperately to maintain her looks and figure against insuperable odds.
My delight at the smirks from customers brought me a momentary feeling of superiority, but the image that is burnt in my memory is the look on my mum's face when she discovered the prank.
Having read it in silence, she rolled it up, tossed it in the bin and returned to her duties. I may only have been a teenager, but I recall with searing clarity the momentary look of dismay, humiliation and betrayal etched on her features. It passed in an instant. But it cured me of practical jokes for all time.
The great Mark Twain once wrote: "When grown-ups indulge in practical jokes, the fact gauges them. They've lived narrow, ignorant lives, full of leftover standards that would have been long since discarded with their boyhood if they'd led a fuller life."
His words, sadly, will have a special resonance this week.
Michael Simkins is an actor and writer based in London
On Twitter: @michael_simkins