Sometimes, when someone close to you dies, or perhaps if you have an unpleasant illness, people tell you they are sorry.
That's odd.
They come to you, all serious like, and they say things like "I'm sorry for your loss", or "I'm sorry you're unwell".
They look all compassionate and caring and slightly embarrassed, and they say these things unbidden, when you weren't even looking for an apology, when instead you were blinking in the sunshine and feeling pleased you shined your shoes that morning, or, perhaps you were thinking about cream cakes or freshly mowed lawns.
It's an odd thing, as I said, and you might try to ignore it and move on, go back to thinking about shoes and cream cakes, or wondering why the sun is so bright it flashes off passing cars and casts strange shadows on building facades and shines light in places that prefer to stay hidden.
But you can't go back to such innocent pursuits when the deed is done.
Because the apology plants a little seed in your mind.
Somewhere deep in the cerebellum it slowly sprouts, it attaches itself to one of the 70billion neurons flitting about the brain and takes hold at a subconscious level.
It flashes through your cerebrum and bounces off the inside of your skull before settling in either the left or right hemisphere of your brain, depending on how it feels on the day.
And when it does, you know something has changed.
Shop windows reflect back at you with furrowed brows, passing children look suspicious and take on a sinister air, a pushchair's wheels grind wickedly on the footpath, an elderly man seems to leer at you with vicious intent; everything is wrong but you can't work out why.
That's when it hits you.
People apologise for things they've done.
People apologise for scalding you with hot water, breaking your bathroom window, stealing your newspaper or writing offensive words on your fence.
They apologise for stepping on your foot or divulging a secret you told them not to, for spilling wine on your carpet, stealing your wife, mocking your children or being rude to your cat.
They say sorry for casting a spell on your mother-in-law, or leaving a dead mouse on your front step as a sort of a warning for an unspecified slight or slur they felt you perpetrated against them at a drunken party the summer before.
Those are the things people apologise for.
So when they start apologising for a death in the family or the sudden onset of a potentially fatal disease there's only one possible reason; they caused it.
If your mother or a favourite aunt died recently and a so-called friend approaches you in the street and apologises, know you are looking straight into the empty eyes of the fiend responsible.
If your heart has recently stopped and only the intervention of a group of highly-trained surgeons has saved you from the jaws of oblivion, if your spleen has been found to be of irregular shape, if you have come down with mumps, malaria or measles, if your liver has given up the ghost and your time on earth has been rapidly depleted and someone comes up to you in the street and says sorry, know for certain that person is directly responsible for the untimely dissolution of your parts.
It is possible to deal with the issue, perhaps by taking out a contract on the perpetrator with a shadowy group of dangerous men, or by creating an effigy of them and sticking pins in it, or performing some other act of sordid, supernatural degradation that will ensure their demise.
But things can get awfully complicated.
At events like funerals, or parties you have organised to celebrate the onset of an illness, tens, perhaps hundreds of people will clasp your hand, look you directly in the eye and with no hint of the sickening shame they should be feeling, say "I'm sorry for your loss", or "I'm sorry about your illness".
Each time it happens, a nauseating chill will grip you, your stomach will turn and your knees will wobble weakly as you fight the natural inclination to pass out, because you are dealing with the awful understanding that the problem is much bigger than you thought.
The apologies are coming left right and centre now from people you once trusted, close friends and colleagues, even wider family members approach you with their forked tongues and hypocritical, sanctimonious talk, their hollow regrets and shameless insincerity.
There are thousands of them, seeping from the pores of society to inflict upon you death and disease.
It's a vast, unstoppable conspiracy of people who are so terribly sorry for precipitating the worst that fate can offer.
They've got together and developed a multi-faceted plan to ruin you and yours, to send you and your loved ones to an early grave, to end all that is good in your life, to lay waste to your metaphorical crops, salt your earth and poison your water.
They have no conscience, and no compunction.
So keep an eye out for these maniacs who would individually, or as a group of conspirators, go to any lengths to do you in.
Watch for them as they approach you in the street with their meaningless sympathy and their cold wet hands and their kiss of death.
Keep your head down at funerals of loved ones, or wear a hood and dark glasses so you won't have to face the treachery of those that should be on your side.
And never forget: run a mile from anyone who would ever even consider saying that tired, hackneyed and pointless phrase: "I'm sorry for your loss".