Oh my stars!
I have a theory that as we get older, the tendency to dwell on the past in inversely proportional to our self-perceived prospects for having anything interesting happen in the future.
That is, people who are still active, have an up-beat attitude, are engaged in interesting or meaningful activities, and who envision that they will continue to do so for some time, have less tendency to wallow in the past.
People who think their life is pretty much all over, who see themselves as just lingering around waiting to die, who see no prospects for anything interesting to happen to them any more, those people will have more of a tendency to wallow in nostalgia.
Saw a “Desert Storm Vet” sticker on a fairly new truck not too long ago.
Really dude? Time to let that one go.
In my college dorm, there was a guy who kept going on and on about his career as a kicker for his high school football team. Not a quarterback, not a star linebacker, but a kicker. Anyway, my friend and I would often joke that the guy’s theme song was the aforementioned Glory Days. I guess it was somewhat understandable because he was just a year out of high school, but still…
Yeah, but I bet he could throw that speedball by you.
mmm
I continue to have interesting things thrust upon me. :mad:
Had you made General, in the Navy; now that would be worth bragging about.
Gawd. At least half the stuff I did in my 20s I’m not willing to tell anyone. 
I was VERY proud of my high school varsity jacket as a freshman in college. I wore it with pride, just like in high school. Then I noticed all the other freshmen guys, wearing their varsity jackets … with pride, just like in high school. Then I stopped wearing mine! 
I think this is it. People brag/wallow about what they perceive as their peak self important event. (If you think it’s already happened, you’re not living your life right, in my most humble opinion.)
But if you truly believe nothing more interesting than ‘X’ will happen to you, then of course you’re going to keep revisiting it and broadcasting it lest others forget your glory moment.
The sad part is, once you begin to do so, I suspect you assign yourself to the ‘hasbeen’ pile, and, indeed, you insure nothing truly noteworthy is ever likely to come into your life again, accomplishment wise.
Excepting possibly a spectacular exit via freak accident, I believe we’re all in that lottery! 
I really felt sorry for a friend of mine from high school at our 30-year reunion. He was the senior class president, star jock, on the homecoming court, yada yada. At the reunion he said that high school was the best time of his life, and it’s all been downhill since then - for the last 30 years.
And this is all one reason why I tell people that the meaning of life is found in the small moments that happen every day, not in the great moments, not in the huge victories that you live in the shadow of or work to have more of.
In the small moments. Sitting in your favorite chair doing something you enjoy. Watching a sunset. Spending time with your lover. Lazing in a comfy warm bed because you don’t have to get up. Listening to your favorite music.
Piling those small movements up, piece by piece is what makes your life worth living, not some award or achievement you had 30 years ago.
Recognition, I think, is a big part of it.
When you’re young and your world is much smaller than an adult’s, you place more importance on those things which make people sit up and take notice of you.
Some people, as described upthread, never outgrow that stage. That’s not to say that you can’t remember stuff like that with fondness, but don’t make it your entire reason for living.
(BTW I used to run into the star jock of my high school class every so often at work. He was Division I hockey back then, got several scholarships to college…and somewhere along the way he crashed and burned. To his credit, though, he’s never talked up his glory days with me).
One of the best putdowns – I was at a school board meeting, and the superintendentg gloated that he had 32 years experience. My friend next to me nudged me and said “He has one year of experience 32 times”.
If you’ve been an astronaut, what are you going to do next that tops that in terms of storytelling? Even if you have a ‘successful’ career after that, and you talk about it to people, they’re going to wonder why you didn’t talk about being an astronaut.
Just the other day, my wife and I were talking about people who peaked in high school. For some of them, it seemed like they understood on some level this was the best their lives were going to be.
Well in a odd technical only way, every US Marine General has done just that. Currently the Marines are separate from the Navy itself but under the Dept. of the Navy.
I worked with someone in the 1990’s who constantly talked about his glories of fighting the “dirty Japs” (direct quote) in World War II forty years ago. Apparently they were to blame for his downhill life since then.
I have always admired people like scientists for example, artists and inventers would fit in here as well. They start climbing a mountain early in life even though they know they will never reach the peak. Peaking out is a horrible experience.
Did you point out to him he was fighting “dirty Japs” in the 50s, 10 years or more after the war ended?