The long-held theory about Guinness is that it doesn't travel well. It's a thing of incredible beauty in Dublin where it is brewed, but stick it on a boat to the New World and by the time it arrives, the structure has collapsed, the flavour has shifted and there is nothing to marvel at.
Still, it keeps being sent over and no matter its reputation, people will pay over the odds for it.
Which, in case anyone hasn't worked out where this is going, is a similar story to what happens with high profile All Blacks.
There has been a procession of world class All Blacks who have headed offshore in the last decade.
Clubs on the other side of the world have broken the bank to buy them, convinced that the pass and catch qualities they so effortlessly display in New Zealand, will bring victories and titles.
And yet here we are, 20-plus years into professionalism and there are few success stories of All Blacks being transforming agents at foreign clubs.
Plenty of clubs have forked out more than they could afford on players who, much like the Guinness, haven't traveled well.
And much like Guinness, there seems to be no prospect of demand shifting to reflect reality.
No matter how many All Blacks head offshore only to be branded duds, the reputation of New Zealand players only grows and the desire to have one on the books of most big clubs only increases.
At some point in the last few years big European clubs really should have twigged that buying Kiwis is fraught with risk as they really do need to be in their natural habitat to perform.
The number of high profile All Blacks who have actually delivered abroad is tiny. Dan Carter, although clearly not at the zenith of his powers, probably left Racing 92 earlier this year feeling like the $7.5million they paid him was mostly worth it.
They won a coveted Top 14 title in Carter's second year and also made the European Cup final twice, although lost in both.
The fact they were nowhere near winning either competition prior to Carter's arrival suggests the investment was wise.
Nick Evans, although not quite in the upper echelon of All Blacks talent when he left for Harlequins in 2008, was paid as if he was and there isn't anyone at the London club who would disagree that the former North Harbour first-five was the best purchase in their professional history.
But for every Carter and Evans there is a Christian Cullen who never settled at Munster; or a Chris Jack who was a disappointment to the club owners of Saracens.
Ziznan Brooke flopped at Harlequins when he was paid top dollar to move there in 1998; Josh Kronfeld hated his time at Leicester Tigers even if he loved his bank balance and Carlos Spencer never quite became the sort of player at Northampton he was at the Blues.
The evidence strongly suggests that paying established All Blacks huge sums to shift to the other side of the world is not good business – a point being reiterated by the ongoing difficulties both Lima Sopoaga and Aaron Cruden are having at the moment, respectively trying to find their form at Wasps and Montpelier after million dollar deals.
But the French in particular, are happy to ignore the evidence and buy on impulse regardless.
They are willing to forego doing any research and be driven by an egotistical need to buy the player with the highest profile.
And the higher the profile, the more they will pay which is why there is a proposal to increase the salary cap in the Top 14 and create a mechanism for clubs to pay even more ludicrous sums for so-called marquee players.
This will cause some angst in New Zealand rugby circles – especially when Kieran Read shortly confirms he is joining Racing 92 and Ben Smith that he is headed to Pau - and another flurry of debate about whether the game here is losing its hold on the best players.
It will bring to the surface tired old arguments about it being time for the All Blacks to pick players from offshore clubs because New Zealand Rugby is losing the retention war.
But far from causing any angst, NZR should welcome the fact that a predatory market is after all the wrong assets. Or at least, keeps ending up with all the wrong players.
The players of most value to NZR, in no particular order are, Beauden Barrett, Rieko Ioane, Brodie Retallick, Sam Whitelock, Sam Cane, Ardie Savea, Richie Mo'unga, Damian McKenzie, Anton Lienert-Brown, Jack Goodhue, Jordie Barrett, Joe Moody, Codie Taylor and Nepo Laulala.
Most of this group have already committed medium-to-long term to stay in New Zealand while the likes of Barrett, Retallick and Whitelock are expected to soon confirm they are staying with various sabbatical clauses included.
The French can increase the size of their respective war chests, but all they want to do with it is buy more Guinness.