The old men from Gun X Sword. They keep drinking and talking about the Glory Days in a deceased member's granddaughter's tavern and are chewed out by the other people who don't even believe them. They prove themselves again when an armor attacks their town and they get to show off the El Dorado V.
A painful example would be from the 2003 Utsuge turned AnimeKimi Ga Nozomu Eien. Hayase Mitsuki, a once-in-a-generation swimming prodigy had the makings of an Olympic-Grade Champion. She leaves it behind to look after her best friend Haruka's boyfriend Takayuki. He is unable to complete high school because of his suicidal depression over Haruka's car-accident induced coma. An accident inadvertantly caused by Mitsuki. Three years on, when Haruka awakens, Takayuki leaves Mitsuki behind to restart life where he left it. Mitsuki, now a mere office lady, meets an old-rival who is now an olympic grade champion-swimmer doubly reminding her of the meaninglessness of her sacrifice.
In Death Note, Light Yagami kills L at the end of the first arc, in his Crowning Moment of Awesome, then spends the rest of the series, and his life, missing the challenge from L and working at a desk.
Cowboy Bebop has a trio of old men (possibly former cowboys) which keep talking of the great days back in their youth.
Until then, that Large Ham had been happily Chewing the Scenery and enjoying having fans; the rest of the cast were long-since sunk in awareness that they were washed up and abiding hate for their 'captain' coworker. (William Shatner approves this message.)
Uncle Rico from Napoleon Dynamite is a particularly sorry example of this trope, as he looks back on a football game that he spent warming the bench. He spends all his free time practicing his throw and lamenting that he could have won the game and gone pro if the coach had put him in.
He even buys a "time machine" on the Internet so he can go back and change his life.
Played with to the point of subversion in Music and Lyrics; whilst former pop-star and professional has-been Alex Fletcher's Glory Days are well and truly behind him at the beginning of the movie, he is, if not exactly ecstatic with his lot, comfortably resigned to it. Having found some measure of contentment in the low-rent theme-park gigs he does to support himself, he doesn't demonstrate a burning desire to get back to the old days, and seems to have accepted the fact that his Glory Days are behind him. His main motivation throughout the movie is not getting back on the charts, but ensuring he has a sufficient enough profile to secure a lucrative contract singing at Disneyland.
In This Is Spinal Tap, the titular band spend most of the movie actively determined to pretend that the Glory Days aren't well and truly behind them, despite the fact that the crowds and venues are getting noticeably smaller.
As are the stage sets.
Randy "The Ram" Robinson, the aging, lonely, deteriorating title character of The Wrestler.
Sam Rothstein laments the old Vegas at the end of Casino.
Robert De Niro's character in The Fan, to an Axe Crazy degree.
The Teenage Mutant Ninja Turtles were going through this in TMNT, which is odd, since there was no indication from the last movie that things would turn out this way.
"Fast" Eddie Felson in The Color of Money. We saw his Glory Days in The Hustler but when The Color Of Money opens, he's a bitter burnout selling booze and ends up working as a stakehorse to a younger player. Subverted when he makes a comeback towards the end of the film.
Mr. Incredible from The Incredibles exemplifies this trope. After a forced retirement from his career as a super-hero, he settles down and becomes a typical cubicle dweller. While his wife has adapted to their new circumstances, he is stuck re-living his past glories, a fact which the villain exploits to get Mr. Incredible to unknowingly help him.
Helen: Risking our family again so you can relive the glory days is a very bad thing!
Bob: Well, reliving the glory days is better than acting like they didn't happen!
Actually, the central theme of the entire movie is adapting to new circumstances without losing your sense of identity. So, in a way, it both embraces and disregards the idea of Glory Days.
Even the title of the music for the prologue sequence is "The Glory Days".
Parodied in Hamlet 2; Elizabeth Shue plays herself as a survivor of the Hollywood Hype Machine having decided to quit acting and become a nurse instead. The main character is a huge fan of hers and invites her to the school to give a talk about acting to his drama class — which ends up embarrassing for all concerned, as the kids have no idea who she is.
One of the main themes in The Turning Point. Emma was once a great dancer, but now she's in her mid-forties and can barely execute a double pirouette. Her old friends Wayne and DeeDee, also once on their way to ballet stardom, abandoned their performing careers shortly after having their first child. And Michael, the artistic director, has devolved from a great choreographer into an administrator.
In The Fighter, Dickie Eklund constantly replays his boxing match where he managed to score a knockdown against Sugar Ray Leonard, despite the fact that Leonard eventually won the match. Everybody gets tired of Dickie constantly talking about the fight and later, he runs into Leonard and Leonard can barely recognize him.
Tan'elKoth in Blade of Tyshalle literally fits this trope to a T. He used to be a god. As a line points out, his very name was changed to an unwilling admission that he no longer is that being. Hari also longs for the glory days of his career, when he was an unstoppable assassin instead of a paraplegic bureaucrat. See also Orbek's obsession with reviving the Black Knife nation in Caine Black Knife
Many characters in The Great Gatsby, but especially Tom Buchanan, who used to be a star football player for Yale. Nick's impression of Tom is as a restless man who goes about his entire life looking for another football game to win.
Gatsby himself inverts this. He never had such pure happiness in his past, but he's ignoring reality in order to try and make the future glorious and perfect and lovely.
Subverted in Children of the Lens, last in the Lensman sequence: the surviving crew of the battleship "Dauntless", now top brass, cast off their regalia and revert to their original roles aboard ship of twenty years before in order to re-enter a strange universe and craft the ultimate weapon. They literally get to relive their glory days, even as they are living a second set.
Buffy has moments of this, at least at the beginning of the show, missing her popular cheerleader days, back when she didn't have to be a slayer.
Star Trek: The Original Series, episode 2x24, "The Ultimate Computer," had Dr. Richard Daystrom who invented the duotronic computer system used on Federation starships when he was 24, and spent the next 25 years trying to recapture that moment of brilliance (leading to the disastrous results of the M-5 computer). However he seems to have made some historical impact, as by the 24th century a prominent scientific institute is named for him.
Did you know that Al Bundy of Married... with Children once scored four touchdowns in one game of high school football? Al sure wants you to know.
Illyria, a Cthulu-esque goddess demon from Angel, awakens from millions of years of stasis to find herself trapped in a human body, her cult all but extinct and her armies long since turned to dust. She spends a lot of time moping about how powerful she used to be. It's actually quite poignant to see how she deals with the modern world.
In NCIS, it's amazing that Ducky has even had the time to experience all the things he's always rambling on about. He's not that old...
Q: How many Centauri does it take to change a lightbulb? A: Just one... but in the Glory Days of the Republic, hundreds of servants would change thousands of lightbulbs at our every whim!
The main theme of The Twilight Zone episode "The Sixteen Millimeter Shrine", in which aging actress Barbara Jean Trenton longs for the days when she and her friends were young, beautiful stars.
Highlander actually has an episode called "Glory Days", where Joe Dawson, who was the star quarterback of the high school football team, meets up with the head cheerleader he'd once dated. He gets depressed because he lost his legs in Vietnam, and doesn't think she'll like him, that he's 'damaged goods' (she was actually married anyway, but she does reassure him that he isn't damaged). Meanwhile, Mac is targeted by a former mobster immortal who's depressed and unhappy and wants Mac dead for instigating the 'death' that got him kicked out of the mob back in the 30s.
On Glee, Terry accuses Schuester of obsessing over the Glee club in order to revive his Glory Days from high school.
Deconstructed in Bruce Springsteen's "Glory Days". The song describes a group of high school classmates who were really big deals at the time, but have since gone nowhere in life, so they get together, get drunk and reflect on their high school days to feel better about themselves.
Also deconstructed in U2's "Stuck in a Moment You Can't Get Out Of"
The Bowling For Soup song "1985" is about a woman who misses her youth back in the 80's.
The Bob Seger hit Like a Rock features a man reminiscing about his youth.
Jason from the Argonautica met his end because of his obsession with his Glory Days. After Jason's lack of faith to Medea destroyed his life, he found himself years later on the beach where the hulk of his old ship the Argo lay. As he sat reminiscing about his adventure, the rotting prow of the Argo fell on Jason.
Willy Loman in Death of a Salesman is so obsessed with his glory days that he occasionally flashes back to them. Whether or not the glory days actually had that much glory in them, or if Willy and his son are re-imagining the past is an important part of the story.
Guybrush at the start of Monkey Island 2: LeChuck's Revenge. After he beat LeChuck in the first game he had a great life, but people were expecting more and eventually he lost Elaine and people forgot about him. This one of the factors motivating him to find the Big Whoop.
Langdon Ricketts of Red Dead Redemption. He clearly misses the old days and refers to himself as an old relic sitting around Chuparosa as some 'low-rent would be messiah.'
In The Gamers Alliance, after Agarwaen becomes the king of Manster, he gradually grows bored with his kingly duties and yearns for the days when he was a free adventurer.
This was subverted in a recent thread on the board, in which both V1 and V2 were criticised - V1 for being too spontaneous and for a lesser writing quality, and V2 for being overplanned. To quote the Admin of the site, "for the most part, V3's found a good mix of both planning and spontaneity". Read the thread here.
The main theme of There Will Be Brawl. Mario, Link, and a few other characters in particular seem to have taken it hard.
The Best Page In The Universe was one of the most talked about websites of the Web 1.0 era. His attempt to translate his old popularity into Youtube popularity haven't fared well, as his real persona doesn't match well with his over the top troll style used in the writing that made him popular back then.
Camp Lazlo: on the episode "Dead Bean Drop", Slinkman, of all people misses his days as a death-defying daredevil, but he seems to have shoved it into the back of his mind over the years until Lazlo, Clam, and Raj find out and begin talking about it nonstop. He apparently moves past it when after fifteen years of having quit, he manages to jump the titular cliff, and it is never mentioned again.
The Renaissance saw Ancient Rome as the Glory Days of mankind, hence the popularity of the term "Dark Age Europe" and "Medieval Morons". Petrarch even said "What else, then, is all history, but the praise of Rome?"
Some people in the United States when it comes to World War II. Now both the left and the right agree it was a good thing we were involved.
Some professional athletes attempt to forestall the end of their careers trying to prove they can still play at the same level despite the drop off in skills.
This sentiment was actually one of the motivations for Germans in the German Workers' Party following the country's defeat in World War 1. Hitler ended up becoming enamored with the groups belief, and after ascending the ranks, the Nazi Party would be formed.