"Give God a laugh," they say: "tell him your plans."
Joe Root could be forgiven for reflecting ruefully on the expression as his England side head into the first Test in South Africa. It would be unfair to suggest his squad has been thrown into disarray by events of the last few days - they still have most bases covered - but, through no fault of their own, the challenge they face in South Africa has become significantly more complicated due to a bout of sickness that appears to be working its way through the tour party. It is a far-from-ideal start to a series England probably have to win if they are to stand a realistic chance of qualifying for the final of the World Test Championship.
First the good news. James Anderson, Stuart Broad and Jofra Archer all came through a long training session on Christmas Eve unscathed. Anderson really does look as fit and strong as ever, Broad looks fully recovered from the illness that laid him low, and Archer doesn't look far behind him. At this stage, it seems all three will play.
But there's bad news, too. Chris Woakes wasn't at training, having reported symptoms of the sickness that has afflicted half-a-dozen of the rest of the squad. He will now spend Christmas Day in isolation - the rest of the squad will train - and has to be considered most unlikely for the Boxing Day Test. Woakes might well have been utilised in a Neil-Wagner-style enforcer role here - he delivered a torrent of bouncers in the latest warm-up game - and would, no doubt, have added some depth to the batting. Sam Curran looks set to play in his place not least as, unless he does, England will have to pick between Jack Leach and Archer to bat at No. 8.
"Despite the evidence suggesting spinners enjoy little success at Centurion - it is the worst ground for them, both in terms of average and strike rate, among the 41 that have hosted at least five Tests over the last 10 years - there is a case for including one."
More seriously, Ben Stokes also missed training after his father was taken seriously ill in Johannesburg on Monday. It goes without saying, in this day and age, that the welfare of the Stokes family - most of which was here to watch the series - will be prioritised in the coming days and it will be left up to the player to decide whether it is appropriate for him to appear in the game. But it also goes without saying that the show will go on. And there is no easy way to replace Ben Stokes.
With Woakes unfit, it seems the most likely reaction to Stokes' unavailability would be a recall for Jonny Bairstow at No. 5. That would, in theory at least, shore up the batting. But it leaves England with a four-man seam attack on a pitch that, after the first morning, might look pretty flat for two or three days. Truly, no man has been as hard to replace for England from the Test side that reached No. 1 in the world as Graeme Swann.
Despite the evidence suggesting spinners enjoy little success at Centurion - it is the worst ground for them, both in terms of average and strike rate, among the 41 that have hosted at least five Tests over the last 10 years - there is a case for including one. For a start, the next few days are set to be hot (mid-30s) and the inclusion of a spinner might ease the workload for the seamers. Equally, it might also provide some variation from an attack that might otherwise include three men expected to bowl between 80-90 mph.
It was telling, however, that Root referred to the health of Leach as his first concern. Leach, you may recall, spent the second Test in New Zealand in hospital after suffering a bout of gastroenteritis and has been unwell again on this trip. His situation is complicated by a long-standing struggle with Crohn's disease which may extend the period from which he suffers from such incidents. And while Matt Parkinson remains a promising white-ball bowler, there isn't a huge amount of evidence to suggest he is ready for Test cricket. He has so far claimed two wickets for 225 runs in his 52 overs of red-ball cricket for England.
"We've got to find out where everyone is at first with this illness," Root said. "In terms of the balance of the side, we'll have to make a very late call on our team."
It would be harsh to level any criticism at England for the state in which they find themselves. Maybe they could have ensured the original squad had a reserve seamer who was match-ready for this first Test - Mark Wood is still some way from full fitness - but by calling up Craig Overton (and Dom Bess) as soon as they realised the severity of the sickness within the squad, they reacted as well as could be desired. In truth, they've just been unfortunate and, from Root at least, there is no question of using circumstance as an excuse.
"We're very lucky we've got a big squad out here," Root said. "And we've a number of guys in a really good place and ready to go. We've some competitive players who are desperate to prove a point. We're here to play good, hard cricket and to win this series."
In Anderson, at least, he has a gem. At an age when other seamers might be thinking of the weeks of rehab as unbearable, Anderson still has the desire to have spent months recovering from an injury to drag himself to this position once more. We can leave debates over his place in the pantheon of seam-bowling greats to another day - though his stats suggest he merits a mention among the best of them - but his hunger, his determination and his unquenchable love for this great game cannot be denied.
"He's incredible," Root said. "He's had a significant time away from the game and for a guy as experienced as him to use that time to go away and improve himself physically is a really good example to the rest of the group.
"It must have been difficult for him to miss a huge series like the Ashes. But he's taken that time to work on his strength and fitness. He's in as good a shape as I've ever seen him.
"A lot of it comes down to drive and desire. It's testament to him as a person and to his work ethic. He's a great example to any young cricketer at the start of their career."
Mark Boucher recently alluded to his South Africa team as a wounded buffalo. England may well see themselves as a sickly lion. Which is most dangerous is hard to gauge.