After a full day of drinking, getting sunburnt and general larking about, it's the final act of the day that pulls everything together for two hours of hits, pyrotechnics and spectacle. The headline act: ready to triumphantly smash all before them.
Or, at least, that's the theory. But genuine headline acts could well be an endangered species, given the results of recent analysis from music industry bible Music Week.
They studied the main stage headliners for the UK's five mainstream festivals (Glastonbury, V, T in the Park, Isle of Wight and Reading & Leeds) and found just five acts that released their debut albums after 2006 had topped the bill. Yes, you do the math(s): out of 140 headline slots since 2006 just five have been occupied by 'newcomers'.
And, to add insult to injury, the list of five is comprised of Mumford & Sons, Calvin Harris, Avicii, Noel Gallagher's High Flying Birds and Florence and the Machine. The first three - fair enough - but Noel Gallagher has been releasing albums since 1994 with Oasis (and his set features many of their songs) and Florence was only promoted after Foo Fighters had pulled out.
So, does this matter? After all, there were clearly 135 headline spots filled very nicely thank you very much. And it is the regular refrain of the seasoned festival-goer that "it's not all about the headliner, I'd rather watch X, Y or Z in the Moombahton tent than watch those sell-outs on the main stage." But the fact remains that for most punters, it's the headline acts that sell the show - after all, they get the biggest crowds of the whole event and what was all the talk about at this year's Glastonbury (well, other than Lionel Richie)? It was Mr Kanye West; if he'd been playing a day slot no one would have said a word and there'd have been no ridiculous petitions.
West's booking at least hinted at festivals looking to break 'new' ground of sorts; it was the first time he'd headlined, but lest we forget, The College Dropout came out way back in 2004.
The ageing of the old guard has become a major concern of the live industry in the last few years; particularly in the world of rock music. To look at the Download and Sonisphere line-ups of the past few years is to see a revolving cast of Iron Maiden, KISS, Aerosmith, AC/DC, Metallica and Def Leppard, all of whom are one over-exuberant stagedive away from popping their clogs. It's not inconceivable that the lot of them, along with the likes of The Who, Paul McCartney, The Rolling Stones, U2 and Fleetwood Mac could all be out of the game within five years. And who steps up to replace them?
Major arena and stadium tours make up the majority of the live sector's income, but to justify shelling out upwards of £50 a ticket, an act needs a solid two hour set of solid gold hits - and not many acts are surviving long enough to produce this body of work.
Interestingly, the years 2001-2005 saw debut records from a healthy 19 acts that went on to headline festivals including the likes of The Killers, Arctic Monkeys, Kings of Leon and Kasabian. But even of these 19, we'd rate probably only 10 of them as arena or stadium-sized acts today.
So what has happened? Clearly, audiences aren't sticking with acts for long enough for them to become bona fide headliners. And the fault must lie in one of two places: the audience themselves, or the acts.
We'd argue it's a little of both.
The ever-increasing and easy availability of music has meant that fans no longer need to concentrate on one particular album or artist. Why listen to the same record ten times and grow to love its nuances when there's something newer and shinier to listen to instead? If an act takes their time writing their second or third album, it's very easy for them to be forgotten, given the huge media space for NEW NEW NEW and the much smaller space given to 'returning' artists. It is a major bugbear that Radio 1 has a slogan of 'In New Music We Trust' - why not just trust Good Music?
But, perhaps, the audience are right. Maybe acts just aren't producing enough quality to keep them interested over a prolonged period of time. There's been a host of decent first albums which are over-hyped, then over-sell, putting pressure on the act from the label (and, as described above, from the audience too) to follow it up quickly, resulting in a backlash when the second record isn't the second coming of Christ. Too much attention too early can also give acts a delusion of grandeur, resulting in sub-standard material and a quick dose of reality when the sales figures come in; by which time their moment in the sun has gone. In the old days of the slow build-up, there'd be time to make mistakes out of the public eye and a chance to refine craft both in the studio and on stage.
A third option is the possibility that festival bookers have been slow to promote acts worthy of headlining; but these guys tend to know what will shift the tickets, and nothing would be worse than an act that's not ready for it headlining too early and being suffocated by the experience.
Once again, short-termism and impatience - from both the industry and the punters - look like the real culprits here, and we'll all be worse off when the festival lineups for 2025 are announced, with the sad absence of any huge acts that can unify a large and diverse group of people, even if only for two hours of a hazy summer day.
Follow Dave Fawbert on Twitter: @davefawbert