We've all got that mate who says they beat Lewis Hamilton to a parking spot or nutmegged Harry Maguire to score an absolute "worldie" when they were kids.
It's the sort of story that gets longer and more elaborate as the years go by.
And as the Tokyo Olympics gets under way, people across the country are honing their own tales of when they were teenage sensations and getting the better of someone from Team GB.
Even if it was just the once.
In what we're calling the swimming version of the Messi-Ronaldo battle for the ages - Jamie Aldred, from Buckinghamshire, squared off in the pool against Tom Dean, now an Olympic swimmer representing Great Britain.
"When I first started, his name was always number one, he was winning every competition," 21-year-old Jamie tells Newsbeat.
So it became "a personal goal" to try and beat him.
Tom had the upper hand aged 12 and under, but Jamie started getting better - and by the time they were 14, "Tom started noticing me".
You can practically taste the tension as a "friendly rivalry started happening" at county and regional championships.
And then the Hollywood ending.
"I beat him in the front crawl, that was a proper proud achievement for me," says Jamie.
And in true Olympic style, things were very respectful away from the white heat of battle.
"We came from different clubs but would always see each other in competitions. We tried our best but whoever won at the end, we'd congratulate them and then go again," adds Jamie.
Of course, those rare victories seem sweeter now Tom's competing at The Games.
"I sent a message of the video that shows me beating him. And he laughed, he's a really nice guy."
For Taylor Andrews, 18 years of racing BMX means he's ramped off against two of Team GB's BMX Olympic hopefuls, Beth Shriever and Kye Whyte.
But it's the memory of beating Kye which really stands out for Taylor.
"When I was 19, I was racing in a championship and he came at 15 and was racing too," the 25-year-old tells Newsbeat.
So was it a performance of a lifetime to beat someone as talented as Kye?
Luck may have played a tiny part. "Kye might have crashed to be fair," admits Taylor.
"But he was in the race. And if he does win gold, that will be my claim to fame."
Taylor will no doubt be failing to mention the big age gap in that famous victory - but is still delighted that Kye "flew on to bigger things".
Taylor and Beth both had the same coaching sessions at their original club in Braintree in Essex.
So does he credit himself for inspiring any of Beth's success?
Not quite. He didn't really need to do anything as she was already "really confident and smashing it".
"She was winning nationals and was opening everyone's eyes to big jumps and situations you wouldn't normally put yourself in at that age."
Taylor says it was obvious that both Beth and Kye were going to make it to the top.
"You always get a sense when someone is great, if they've got the right attitude and want to commit themselves as much as Beth did at the time. You knew she was going to be destined for greatness."
And there's no grudges or bitterness for Jamie and Taylor at seeing their former rivals fly and go for gold in Tokyo.
"There's something inside you that makes you want to win. They've got a good chance of winning," Taylor says.
Jamie says he won't be bragging too much about beating Tom if he were to win a medal, but he'll be sure to put on social media how proud he is.
"I've followed him and saw he smashed the European Championship record, and that was a really proud moment for me as well. Just to say I know that guy and he's gone on to Team GB."
"I'm going to be cheering him on all the way," he adds.