He pined to go back in time without realizing he was already there.

"I wish that I could press rewind somehow," Boys Like Girls frontman Martin Johnson sang on Saturday, performing the pop rockers' buoyant 2009 single "She's Got A Boyfriend Now."

A decade-and-half later, his wish was granted at the Las Vegas Festival Grounds, where 60,000 fellow time-travelers flocked to massive emo and pop punk gathering When We Were Young to spend 10-plus hours singing into their fists in place of hairbrushes in teenage bedrooms.

"We're aging gracefully," Johnson said in-between tunes. "If you don't look fantastic, I hope you feel fantastic."

And really, that's what When We Were Young is all about: providing a little chicken noodle soup for the emo soul, an opportunity to hit pause on the demands of adulthood for a day, swapping grown-up angst for that of the adolescent variety.

"I'm just a kid and life is a nightmare," read T-shirt from pop-punks Simple Plan, the word "kid" crossed out and replaced with "adult."

But, as When We Were Young continues to demonstrate, if life doesn't always get easier as you get older, the music that got you through those awkward teen years can sometimes do the same decades later, even if it's mortgages weighing on the mind in place of dismissive high school crushes.

"All I need is just to hear a song I know," Jimmy Eat World frontman Jim Adkins sang on "A Praise Chorus," his words doubling as a succinct encapsulation of this festival's appeal.

Back for year three, When We Were Young featured a new twist this go 'round.

"It's all about the throwbacks today," explained Movements singer Patrick Miranda, noting how most bands were performing one of their most beloved albums in its entirety, his band airing their aptly titled 2017 debut "Feel Something."

This meant picking more than a few scabs in song.

"I don't often spend time with the boy inside of me who wrote this record," confessed Taking Back Sunday Adam Lazzara, referencing his band's 2002 debut "Tell All Your Friends," a platinum-selling emo touchstone. "He's alright."

It also meant hearing plenty of deep album cuts seldom, if ever, performed on stage.

"Here's something we've never played live before," Pierce the Veil singer-guitarist Vic Fuentes said by way of introducing "One Hundred Sleepless Nights," one of two songs from the post-hardcore trio's third album "Collide With the Sky" to make their live debut 12 years after the record's release.

"Let's scream until there's nothing left," he sang on "King For a Day," leading by example, his vocals delivered in a perpetual whelp, like a puppy whose tail has been stepped on by accident.

Cathartically, confessionally expelling intensely personal pain in song: That's what much of this day was about.

"It just hurts to be a man," sighed Bayside frontman Anthony Raneri on "Tortures of the Damned," finding a measure of solace among his emo brethren.

"We all grew up in this scene," he said between songs. "We owe everything to this scene."

Sometimes, the music was as heavy as the emoting: When Pennsylvanian metalcore crew August Burns Red performed their third record "Constellations," it felt like it was raining anvils down on the crowd.

Elsewhere, things swelled to epic proportions, such as when My Chemical Romance closed the night with their 2006 rock opera "The Black Parade," an album of well-heeled rebel yells buttressed with string and horn sections and Elton John-worthy piano ballads.

"When I was a young boy, my father took me into the city to see a marching band," frontman Gerard Way snarled on "Welcome to the Black Parade." "He said, 'Son, when you grow up, would you be the savior of the broken, the beaten and the damned?'"

Yup.

The only bummer about My Chemical's set was that it siphoned everyone away from only the second performance in the last 17 years from Seattle post-punks Pretty Girls Make Grave, whose ruminative rumble was delivered to a sparse crowd, but still thrilled those few who took it in.

One band that didn't perform an album in its entirety was co-headliners Fall Out Boy, though they did play selections from every one of their eight records in chronological order, offering a timeline of their artistic evolution from emo upstarts to stadium rockers.

On Saturday, the band brought Iron Maiden-levels of pyro to the fest, with bassist Pete Wentz outfitting one of instruments with a flame-thrower to spew even more fire from the stage.

If "This Ain't A Scene, It's An Arms Race," as the band contended in the song of the same name, they brought the nukes.

Toward the end of their set, frontman Patrick Stump punctured the bombast with a confession.

"It's weird being not-young," he acknowledged. "I thought I was young."