It is a phrase that has entered footballing cliche. With irritating regularity, it is used at this time of year. "The romance of the FA Cup" does not really cover it, though. Because it is not the romance that makes the competition special. It is the sheer ridiculousness of the FA Cup.
Consider the events of last January. Leeds United had been champions of England (in 1992) and Champions League semi-finalists (nine years later) without winning at Old Trafford since 1981.
Then they went to their greatest rivals' home as a League One side - the third tier of English football - and knocked out Manchester United.
"They fought like tigers," said Sir Alex Ferguson, the Manchester United manager.
They played like world-beaters. And six days later, some context was applied: Leeds were held at home by Wycombe Wanderers.
And then, just as the gloating from Merseyside towards Manchester was becoming audible, came part two in the round of shocks: Reading, threatened with relegation in the Championship, won at Anfield. It was a maiden victory for their caretaker-manager, Brian McDermott: not just against Liverpool, but for any Football League side, against anyone, anywhere.
History may record the 2009/10 FA Cup campaign as an anomaly. But it was not a one-off.
Think back a further two years and the story is just as remarkable. Barnsley's was a campaign of underwhelming, lower mid-table mediocrity in the Championship that was transformed by their Cup run.
In the fifth round, it took them to Anfield. An injury crisis left them with an on-loan debutant, Luke Steele, in goal. He departed as man of the match with Rafa Benitez, the Liverpool manager, lamenting "some fantastic saves; the sign of a fantastic goalkeeper".
And a side who were in the process of eliminating Inter Milan from Europe were beaten by a spectacular winner in injury time, in front of the Kop and scored by a boyhood Liverpool fan, Brian Howard. Too corny a script to have been written in fiction, it became fact.
Moreover, there was a sequel. The next stage pitted Barnsley against the eventual Champions League finalists, Chelsea.
Their embarrassingly unproductive target man Kayode Odejayi had failed to score in his previous 28 games. He duly headed the winner.
Barnsley had defeated a team including John Terry, Ricardo Carvalho, Nicolas Anelka, Florent Malouda, Michael Essien and Michael Ballack. They had already overcome Steven Gerrard, Jamie Carragher, Xabi Alonso, Dirk Kuyt and Peter Crouch. The strong sides they faced added to the implausibility of it all.
So, too, did their subsequent fortunes. Odejayi is now failing to score goals for Colchester United; Simon Davey, the manager, was sacked by Hereford United, a club headed for demotion from the Football League, in October.
Yet the FA Cup granted each his moment. Just, indeed, as it has to countless others. This is a competition where there is a licence to dream, where fame can be conferred on the unlikely and the favoured can look foolish.
There is a long-standing tradition of the unlikely, creating indelible memories and offering a limitless possibility for embarrassment. It is a self-perpetuating system for discomforting the privileged.
Think, for instance, of Bournemouth knocking out Wolverhampton Wanderers and Tottenham Hotspur, two of the dominant teams of the day, in 1957, before losing narrowly to Manchester United's Busby Babes.
Or of Bournemouth again, defeating the holders Manchester United in 1984, the first famous win of a young Harry Redknapp's managerial career. Or Wrexham, bottom of the Fourth Division, defeating the defending champions Arsenal in 1992 courtesy of Mickey Thomas's marvellous free kick.
Consider the prowess of the non-league teams. Yeovil's 2-1 win over a star-studded Sunderland side in 1949 catapulted them to attention. Hereford defeated Newcastle United in 1972 with one of the Cup's most famous goals, Ronnie Radford's piledriver on a mud-heap (though team-mate Ricky George actually scored the winner).
Seventeen years later, Sutton United knocked out a Coventry City team who had won the competition just 20 months earlier.
Nor are such deeds completely confined to the past. Manchester United recorded goalless draws in successive seasons with non-league teams, Exeter City and Burton Albion, in the last decade, though they progressed in both replays.
The broader picture now is that the latter stages tend to be dominated by the elite. In the last 15 years, there have been only five winners; the Big Four (Manchester United, Arsenal, Chelsea and Liverpool) and Portsmouth, triumphing with a team they could not afford. In contrast, there were eight different winners in the 1950s, eight again in the 1960s and nine in the 1970s.
The days when Second Division sides such as Sunderland, Southampton and West Ham could claim the trophy now belong in another era along with the one-off triumphs of Coventry and Wimbledon in consecutive finals two decades ago.
And yet that emphasises the rarity of days such as today. This, now, is when the greatest upsets occur, when lower-league teams are their supporters are infused with belief, when wealth and status provide no immunity to shocks.
This is the time when the English's inherent sympathy for the underdog is most apparent.
This is the time when, as happened in 2003, a Shrewsbury team who would be demoted from the Football League that season could defeat Everton in a season when David Moyes was voted Manager of the Year. That Shrewsbury were managed by Kevin Ratcliffe, one of Everton's greatest captains, only added to the occasion.
But then the FA Cup throws up such plotlines in abundance. This weekend's ties contain plenty. Sunderland against Notts County is Steve Bruce versus Paul Ince, FA Cup-winning teammates in opposing dugouts.
Under the guidance of Mark Robins, a third hero of Manchester United's 1990 Cup run, another bunch of Barnsley upstarts travel to West Ham United.
Avram Grant is not the only manager in a perilous position. Gerard Houllier takes Aston Villa to Sheffield United; surprise strugglers in the Premier League versus their Championship counterparts, with a guarantee of a hostile atmosphere at Bramall Lane.
With Wolves at Doncaster Rovers, there is the potential for a hat-trick of scalps for the South Yorkshire clubs. In nearby north Lincolnshire, Glanford Park, the most cramped and least glamorous ground in the Championship, hosts Everton as the midweek conquerors of Tottenham take on Scunthorpe.
Newcastle visit Stevenage, who, as a non-league side, held the visitors when they were the second best team in England 13 years ago.
The mantle of non-league's leading challengers has passed to York City, who cross the Pennines to face Bolton Wanderers.
And there are tomorrow's match-ups. Roy Keane's sacking yesterday as Ipswich manager has deprived fans of a reminder of titanic battles the former Manchester United midfielder used to have with Dennis Wise at Chelsea's Stamford Bridge.
Manchester City's Roberto Mancini, meanwhile, returns to an old club, Leicester. City And while the notion of Mancini, a quintessential Italian fantastista in the down-to-earth East Midlands city still seems strange, he meets his mentor: Sven-Goran Eriksson, who managed Mancini at both Sampdoria and Lazio and whose derby double over Manchester United makes him one of the most popular coaches in City's recent past.
So while Manchester United versus Liverpool is the round's marquee game, it is not really what the FA Cup is about. It is about Stevenage and Scunthorpe, about York and Dover, just as it has been about Yeovil and Hereford in the past.
It is about men such as Steele, Howard and Odejayi. And it is about the sheer ridiculousness of it all.
The trophy everyone wanted
It may seem strange in an era when the Premier League and the Champions League dominate the attention, but for much of its existence the FA Cup was the trophy to win.
That is partly a consequence of its longevity; it is football's oldest cup competition, with the first final being staged in 1872. Partly because the knockout structure gives everyone a chance. And partly because, especially in the days when the final was England's one televised game in the season, it afforded the greatest opportunity to impress the nation.
But it enjoyed a particularly high status among those who felt the game's greatest prize eluded them. Liverpool would not trade one of their 18 league titles or five European Cup wins for the FA Cup now, but that was not always the case.
"The FA Cup had been Liverpool Football Club's central concern almost since the club was formed in 1892," wrote John Williams in Red Men, a history of the club that was published last year.
A 73-year wait to win the FA Cup ended in 1965 when Ian St John's extra-time goal defeated Leeds. "To think a club like Liverpool had never won the FA Cup was unbelievable," Bill Shankly, the manager, said.
"So when we beat Leeds, the emotion was unforgettable. Grown men were crying and it was the greatest feeling any human could have to see what we had done."