The most asked question in the wake of Neil Lennon's departure as Celtic manager is: "Why now?"
The most pertinent one, however, is: "Why did he stay so long?"
Lennon has been in Celtic's employ for the entire 21st century, save for a quick break at Nottingham Forest. The pressures on him have been extraordinary both as an individual and as a manager.
The disparity between the public and professional perceptions of the Northern Irishman is vast. The taxi driver, the mate in the pub or the guy who buttonholes one at a wedding reception insist he is snippy, even belligerent. He is all of that, particularly when provoked.
But Lennon, as player and then as Celtic manager, was articulate, precise and enlightening in interviews. His criticisms may have read as the perennial rant but they were delivered soberly, even judiciously.
If he was regularly on the front foot in confronting referees, the SFA or whatever issue raised his ire, it is not difficult to state that he was put on the back foot, even placed under siege as a human being. Bluntly, Scotland has much to ponder ruefully in its treatment of Neil Lennon. He was punched by attackers, sent death threats and even targeted by a moron on the Tynecastle touchline. His home life was compromised by security, his professional life spent in the public shadow of a huge bodyguard.
He endured all this and more because he loved both football and the club that employed him. There is no sticky sentiment in this. It is merely a statement of record. But this brought a further pressure on Lennon. He knew precisely how important it was for Celtic to be dominant in Scotland and competitive in Europe.
The demise of Rangers made the first part of this equation relatively straightforward, though Lennon was frustrated that a campaign of almost relentless superiority included cup defeats to Aberdeen and Morton. It is the European dimension, though, that gives a sure reading on the stress on Lennon and on his decision to leave. The Celtic season is now compressed, in financial terms and in supporter fascination, into a period that was once known as the Glasgow Fair and its fall-out. The imperative is for Celtic to qualify for the group stages of the Champions League in July and August.
It was impossible to look at Lennon in the aftermath of the defeat of Shakhter Karagandy at Celtic Park, with a late goal by James Forrest taking the Scottish champions through, and not be struck by how drained he seemed. He was also increasingly aware that the task was getting more difficult.
Celtic celebrated their 125th birthday by defeating Barcelona but the Champions League group stages of 2013/2014 were a sombre indicator of the difficulty of his task. He had lost Gary Hooper, Victor Wanyama and Kelvin Wilson in the summer. His team was weaker and it showed at the highest level.
In this pre-season, Celtic could sell Fraser Forster, the World Cup-bound England goalkeeper, and Virgil Van Dijk, the Dutch defender. This is frustrating for any manager, even one such as Lennon who appreciated the business plan at Celtic.
So he stands now at a critical juncture in his career. Where now? One place he can rule out, however, is Norwich City after Neil Adams' appointment last night.
Lennon, then, has taken a gamble, throwing himself on the mercy of the gaggle of chairmen and chief executives who will be seeking managers in the summer. To those asking "why now", he could respond that in career terms last summer his stock was probably at its highest.
Like most modern managers, he has enough money to enjoy an extended sabbatical but he will be keen to work as soon as possible. He becomes animated on the subject of setting teams up, with a cameo on Match of the Day 2 recently seeming to be a job interview for anyone who would listen. He is also intrigued by man-management, precisely defined by football cynics as how do you make millionaires care?
It is this intoxicating cocktail of football and motivation that both soothes and inspires him. Lennon has known the dark times of depression, has suffered from a temper he has had to subdue, but he finds satisfaction in football.
He chases this with all his might of wit and personality. His Celtic managerial career may be defined by the leagues won, the defeat of Barcelona and his endurance in the face of bigotry. This observer, though, will remember one moment in the bowels of Hampden when Marcello Lippi, Italy's World Cup-winning manager, paused to take questions when giving a master class to aspiring coaches. Lennon immediately came in with two inquiries. The first was to ask Lippi if he felt one of his players at Juventus, Nicola Amoruso, had dived against Celtic to win the decisive penalty in the teams' classic Champions League encounter of 2001. The second was to investigate the benefits and the drawbacks of playing three at the back.
The Italian answered the first with a mischievous smile and a non-committal verdict. He was expansive on the tactical implications of the second.
Lennon seemed satisfied by the answers. He will take this combination of assertiveness, insatiable curiosity, ambition and desire for progress to his next club.
The road ahead may be as yet undefined but it will be forged by a character who was never known to take a step back.