How fine the line can be between elation and anguish will become painfully obvious when the All Blacks v England semifinal match concludes in Yokohama, Japan, a shade before midnight tomorrow. No doubt mad scientists Steve Hansen and Eddie Jones will boldly tread that razor edge of eccentric behaviour and what ruthless fans may go on to label borderline personality disorder, should their experiments fall flat.
At the end of 80-plus minutes, they'll have walked an endless tightrope of dogged determination and stubbornness, confidence and arrogance, theatre and monologue, single-mindedness and serendipity, reality and fantasy, brilliance and blunder, humour and grumpiness, bravery and bloody mindedness as well as character creators and soul destroyers.
All that, of course, will be at the whim of moody fans, depending on whether Hansen and Jones or, for that matter, Wales coach Warren Gatland or South African counterpart Rassie Erasmus, find success or failure.
It is, after all, the silly season. It's the time when TV stations elevate the fortunes (or misfortunes) of teams — especially in this country — above the ruminations of the mechanical grind of the stock exchange markets, the ramifications of global political chaos or even the abhorrent numbness of loss of lives through warfare or natural disasters.
We ritualistically come to expect that and tend to even find some sort of macabre gratification from it all.
Often unflappable — as one tends to expect of New Zealand mentors in the mould of former All Blacks coach Alex "Grizz" Wyllie — Hansen and Gatland have offered enough facial contortions — leading up to and during the Rugby World Cup — to suggest a lot more will be revealed at post-match conferences.
Reporters will have to brace themselves for coaches and players trying to bite off their heads if they ask "stupid questions".
Maybe, just maybe, the mentors will prove everyone wrong to preserve their sense of dignity through composure.
Eating humble pie isn't a given at the higher echelons of sport but it's always on the menu to test one's character.
While All Blacks fans seem to find the luminous flame emitted from Hansen's test tubes, frothing above a Bunsen burner, quite seductive now, only time will tell if that will become combustible and toxic with the onset of anything short of lifting the Webb Ellis Cup at the same venue on Saturday, November 2.
Hansen has dutifully parked himself at the entrance to the match officials' locker room not long after the RWC kicked off on September 20 but will he remain there if a yellow card (or the good lord forbid, red one) goes against the All Blacks to end their campaign to claim a historic consecutive triple crowns?
Losing one's composure remains the domain of Wallaby coach Michael Cheika, to date, and that of Scotland, collectively, for prematurely threatening legal action against World Rugby but any outbursts from those at the helm of the top four nations will be, amusingly, perceived as high-level diplomacy.
Hansen couldn't wait to put captain Kieran Read on a pedestal after the quarterfinal victory but the jury's still out on the affable Cantabrian. Was Read great or were Ireland poor? Surely, it's prudent to test a skipper's worth when the team's under duress rather than when they are humming.
Reign and Read will wear the lifelong smirk of Sir Graham Henry who reneged on his word to step down after the All Blacks' unceremonious exit to France in 2007 but went on to claim the crown in 2011. Succumb and he will undergo a similar litmus test to Hansen and Co on how conspicuous the nice guy has been through his absence.
The knives will be out for Erasmus in South Africa, too, although Jones and Gatland, I suspect, will have earned the respect of their respective countries in getting them predictably to, at least, the semifinals.
The interesting point is the four protagonists will relinquish their coaching berths with their incumbent teams soon after the dust settles at the RWC.
However, accountability — through particularly RWC post-mortem examinations — is difficult to sidestep.
Create history and the media will extol the virtues of Shag's Midas touch. Come up shy and they'll turn on him like a pack of vultures.
You could argue the stars and the moon have mystically aligned for Hansen at the Land of the Rising Sun.
Not only was he able to conduct experiments with the likes of new blood — such as Sevu Reece, Jack Goodhue, Richie Mo'unga and George Bridge — but also pave the way for the likes of Sonny Bill Williams, Ben Smith and Ryan Crotty to book-end their careers at the RWC, in light of injuries and concussion.
Let's not forget Hansen having his way with the Barrett Bromance against Namibia.
Yes, there was some bloodletting. Ngani Laumape, Waisake Naholo, David Havili, Jackson Hemopo, Gareth Evans, to name a few.
Does Hansen have favourites? Resoundingly, yes, and that's his prerogative but stumble and all the factors above can easily become corrosive elements in stripping him naked of what has been a cloak of excellence.
Conversely are the keyboard warriors justified in casting aspersions on matters pertaining to selection, game plans and wild what-ifs?
Definitely. You see, therein lies the paradox of sports, especially when the semifinal carries the burden of win it and you're assured to go on to become the champions.
From where the great unwashed find their perch on their cheap seats, the fine line between genius and lunacy is almost non-existent.
That another team can be better — for whatever reasons on the day — isn't always palatable.
On the other hand, the coaches of this world tend to find a quiet sense of satisfaction in walking into a hail of bullets to finish off on their terms rather than accepting they were perhaps guilty of overlooking the obvious because of hidden agenda.
What is undeniable is rugby will be incredibly poorer at the coal face for having lost such robust movers and shakers in the space of eight days.