The FA Cup doubles up as an insight into the psyche of English football.
It is a tournament where history matters, where the atmosphere can be most exhilarating and where the British's traditional fondness for the underdog can be most pronounced. If it stands apart from its counterparts in other countries, one reason lies in the past.
For much of its existence, winning the FA Cup was more prestigious than taking the league title, even if the latter was the greater achievement. But then this is the world's oldest football competition, first staged in 1871-72 and predating the league's foundation by 17 years.
Now the final stages tend to be dominated by the elite. Since 1995, the Big Four of Manchester United, Arsenal, Chelsea and Liverpool have triumphed on all bar two occasions; in 2008, when Portsmouth lifted the trophy, and last year, when Manchester City, now among the superpowers, prevailed.
Third-round weekend, however, is a time for the unfancied. A historic highlight of the footballing calendar offers opportunities aplenty for a shock or an unlikely hero. Perhaps it will be Bristol Rovers against Aston Villa, the conquerors of Chelsea, or Macclesfield, who take on struggling Bolton.
Maybe Cheltenham can spring a surprise at Tottenham, Peterborough can halt Sunderland's revival under Martin O'Neill or Gillingham can defeat last season's runners-up, Stoke. Possibly Tamworth, the least likely of the lot, can get a result at Everton. It sounds improbable but the FA Cup comes with a guarantee: there will be an upset somewhere, somehow.