Manchester United didn't see it coming. They knew that the retirement of long-serving manager Alex Ferguson was going to challenge the club, they had no idea it would almost destroy them.
United thought they were losing one brick in the wall, but it turned out they were actually losingthe wall.
It's kind of hard not to wonder whether the All Blacks are about to experience something similar. After a decade of unprecedented success, is the retirement of the long-serving Steve Hansen going to be their Manchester United moment?
Is he, like Ferguson, going to prove to be more than one brick in the All Blacks wall? Once he's gone, is the whole thing going to collapse?
No one thought it was possible that Manchester United could fall so far, so fast. And yet they did.
They have thrown money into their squad. They have hired big-name managers and yet they continue to languish. The days of glory brought by the enigmatic Ferguson seem a long time ago and greatness a quality the club may never find again.
Big personality coaches can pervade deeper into the psyche of a team that anyone realises. They come to dominate and control so many aspects of the team that it's only after they leave that everyone left realises they haven't been pulling their own weight.
Hansen has been with the All Blacks in some capacity for 16 years so obviously when he walks away on Friday night, it will leave an enormous hole in his life.
But it would be silly to not realise that he will be leaving an equally significant hole in the All Blacks.
If nothing else, he's pulling out 16 years of institutional knowledge. He's lived through the most radical changes of the age for he was around when the players still thought it was okay to get smashed after a defeat to the extent some had to be placed in the recovery position after they collapsed in the grounds of their South African retreat.
He's seen the booze be replaced by green tea. He's seen Yoga and Pilates replace Play Station. He's seen the old hierarchical ways of young players earning their dues disappear and he's been in the All Blacks coaching box for more than 200 tests.
There's a lifetime of knowledge that is about to go missing and that in itself is enough to be worried about what's next for the All Blacks.
But there's more to Hansen than that. He's been a little like Ferguson in that he's a larger-than-life figure. It's not just that he's gained knowledge in his time, he's gained knowledge about how to use it.
His presence is felt within the team. The players know who is in charge. They know their boundaries. They know the limits and while Hansen has not gone as far as Ferguson and written into his contract that no player can be paid more than him, he's definitely been the All Blacks' Alpha figure these last eight years.
His ship has been tightly run and in the last eight years, there's been endless All Blacks superstars but no prima-donna culture with it.
Team first has rarely been compromised and when it has, Hansen has dealt with it firmly and quickly – establishing himself a little bit more each time as the boss.
Aaron Smith missed a curfew after a test in Wellington in 2012 and was benched the next week. Aaron Cruden missed an assembly time for a flight to Argentina in 2014 and was left at home.
Smith got himself into a whole heap of trouble again in 2016 for which he was disciplined and no one was ever able to flout the rules and get away with it, yet they were all able to find a way to return to the team, chastened and hungry to put things right.
Other teams – even other teams with big personality coaches – haven't been able to run as smoothly in the last decade and this is where Hansen has been so like Ferguson: he's been in total control of the team, able to make strong and consistent decisions that have built respect and understanding from the players.
He's also been backed all the way by chief executive Steve Tew. It's not that Tew and Hansen have been faultless by any means, but they have been united and their respective force of personalities and commitment to the game has often at times been a powerful fuel for the All Blacks to tap into.
The fact Tew is also standing down creates a considerable vacuum as he too is taking 20 years of institutional knowledge with him and an equally bullish personality.
Like Hansen, Tew doesn't give an inch when he believes he's right and a bit like the Jack Nicholson character in the movie a Few Good Men, New Zealand has needed him on that wall.
The All Blacks will have a new coach by the end of the year but that doesn't mean Hansen will actually have been replaced.