Some memories are so permanent in their recollection that they perfectly encapsulate a time and place in a way that you never thought possible.
The one that strikes me the most is an image of Sir Matt Busby, one year before his death, with a beaming look upon his face as Manchester United's Steve Bruce and Bryan Robson lifted the inaugural Premier League trophy in 1993.
Two seismic individuals and leaders of men, making good on a dynasty that had peaked under the tenure of Sir Matt Busby in 1968.
The ethos of the club, the belief in youth, and the core values of the Manchester United had been put in place by Busby during his two spells in charge of the 1968 European champions.
There were managers such as Frank O'Farrell, Tommy Docherty and Ron Atkinson at the helm since his last spell in charge in 1971, but it took the appointment of a Govan born Scotsman in 1986 for the next great Manchester United tenure to begin.
Ferguson is quoted as saying (via The Guardian):
There's absolutely no doubt that what this club is today is built around what Matt started and the vision he had for United. He created a lot of firsts here. It was his idea to introduce executive boxes at Old Trafford, he took the team into European competition for the first time and, of course, under Matt, United became the first English team to win the European Cup.
Surely the next manager of Manchester United will heap the same level of praise upon Ferguson for his achievements at Old Trafford.
12 league titles, five FA Cups, four League Cups and twice European champions. An incredible feat when you consider the riches that have flooded the game in the last 10-15 years.
The biggest questions in terms of Manchester United relate to the time of Ferguson's departure and the man who will replace him.
David Moyes' name has been frequently used in terms of the successor, with Ferguson adding weight to his support (via The Daily Mail) of his fellow Scotsman.
He has a grittiness and determination that has allowed him to be in there all the time. No matter how many players he has had injured he produces a team that has represented the club very well. He is a first-class manager.
Two European cups with different teams and an ability to make players evangelise when speaking of him.
In the other corner, there is Josep ''Pep'' Guardiola. Mastermind of possibly the greatest club side of all-time and twice European cup winner as a manager.
As Barcelona coach he retired with a 72-percent win rate and conducted himself in a way that was as much a credit to Barcelona as it was himself.
The latter is something that Manchester United require in Ferguson's replacement; someone who understands that the club is bigger than any individual.
Joe Mourinho's self-importance, while pivotal to his success as a manager, has contributed to the lack of his own dynasty at any club.
Guardiola's dignified departure from Barcelona and as throughout his time at Camp Nou, makes him the more ideal candidate.
His style as both a player and manager is more suited to the Manchester United way; fast-flowing, forward-thinking, attacking football.
Jose Mourinho's success has been built upon a methodical, percentage based defensive game and is not the type of football that fans at Old Trafford would readily embrace.
Under Guardiola, Barcelona built a team that is composed for the most part of players who are graduates of their academy.
Again, this is directly in accordance with the beliefs of both Ferguson and Busby, and is a a consistent trait of the greatest European teams in history.
While Mourinho would be suitable for almost any other club in the world, Guardiola ticks every necessary box for Manchester United.
The fans will agree and Ferguson is complimentary when speaking (via Total Barca) about the man who will make the ideal replacement for the almost irreplaceable great:
He [Pep Guardiola] has created a different philosophy for Barcelona. I think the [Johan] Cruyff era laid the foundation for the width they used in their game and using the full size of the pitch. If you look at their midfield players over the last 20 years they have all been small. What has changed is the pressing and the areas in which they press the ball. That is what Guardiola has brought to the team.
It will be sooner rather than later that Ferguson will be re-placed and only the correct appointment will ease the transition that Manchester United fans have been dreading since he first mentioned retirement in 2002.