Joseph Schooling and Jessica Ennis-Hill have things in common. They were athletically gifted, hyperactive kids who were helped by grown-ups to achieve their Olympic dreams.
The British heptathlete was teased as "tadpole" when she was just a skinny little child. But she, and Schooling, proved that the journey from tadpole to best in the world takes time, willpower, sacrifice and the right environment to develop.
On Thursday, Ennis-Hill retired. Now 30, a mum and very much the poster girl of British sport, the athlete from Sheffield has gold and silver Olympic medals in her locker, and world, European and Commonwealth medals too.
She knew as a diminutive child at the age of six that she had energy to burn. Growing up to be no taller than 1.65m never proved a handicap even in the seven disciplines of the heptathlon - 100m sprint, high jump, shot put, 200m sprint, long jump, javelin and 800m run.
Mastering all of those, competing against drug-assisted East Europeans, yet managing to retain an aura of the unspoiled girl next door has earned her a fortune in the region of S$10 million.
She can bank on Santander, one of the sponsors drawn to her reputation for grit and integrity, well into retirement.
There it is again, sport helping to wean energetic children away from mischief. But kids who get drawn into it to the extent of Jessica Ennis-Hill, Joseph Schooling and Louis Smith do have to cope with something else. They bypass adolescence.
Schooling's story you know better than me. Singaporean boy wanted to become his country's first Olympic champion, and then beats the human whale Michael Phelps in the pool to do it.
The first million dollars, from the Singapore National Olympic Council, will no doubt multiply. The life story of ambition grown from a determined child to a 1.84m champion began, like Jessica's, in infancy and persevered all the way.
You want to be an Olympic champion?
Then at 14 you and your parents have a decision to make.
Immerse yourself in the United States, go alone to school there and to university. Compete until it hurts in the super competitive swimming regimen which sorts out the tadpoles from the great champions.
Take on, and beat, your idol, Phelps.
If all of this sounds like a dream coming true, then that's exactly the way that Ennis-Hill and Schooling have lived it.
Whatever anyone else has done for them, the achievement is theirs.
The risks along the way are that they might have been broken in body or spirit.
They, and perhaps their families, know the sacrifices.
One of the biggest of those is the right to make mistakes, to be young and foolish and adolescent.
We are reminded of this by what is happening around the gymnast Louis Smith right now.
Smith is 27. He has represented Great Britain at three Olympics - Beijing in 2008, London 2012 and Rio de Janeiro a few months ago.
His speciality is the pommel horse, and Smith brought home medals from all three Games, though he was beaten into second place by fellow Brit, Max Whitlock in Rio.
Last weekend, Smith attended a friend's wedding. At 5am the following morning, still up and still drinking, he and a former gymnast Luke Carson began fooling around in a hotel lounge.
Carson pulled a rug off a wall and - egged on by Smith who was filming the scene on his mobile phone - they larked around.
It was neither funny, nor a lark.
Carson knelt on the carpet, mocking what he thought to be Muslim prayer. Smith giggled, made the same Muslim chants, and filmed the whole thing holding the phone out from his face.
"We were singing Disney songs from The Lion King and Jungle Book," Smith later said in various newspaper and TV interviews.
"We went on to Aladdin and I was saying, 'We need a magic carpet.' Luke pulled a rug off the wall and put it on the floor.
"That's when it strayed a bit far and we went into a shameful thing of mocking Islam prayer. Given the amount of alcohol we had consumed and the silly mood we were in, we found it hilarious at the time."
Worse, Smith sent the video to his group chat. Someone sold it to The Sun newspaper.
The whole thing went viral. The gymnast and the former gymnast were seen drunk, sometimes incoherent, but repeating "Allahu Akbar!" over and over again.
In the media storm that followed, Smith gave interviews to journalists and on television.
He apologised to his mum, to his sport, and to anyone who took offence.
"I like to think that my Mum brought me up to be a better human being than this," he said. "That's been the hardest part of this."
Actually, the hardest part has been the predictable part. Smith, and his family, received explicit death threats from jihadists using the same so-called social media that he stupidly used to post the scene in the first place.
On an ITV lunchtime chat show called Loose Women, Smith was challenged about being a man of 27 acting like a drunken teenager.
"What I did wasn't racist," he insisted. "I've had racist attacks. I'm an ethnic minority myself (he scarcely ever met his Jamaican father). I've been on the receiving end of it."
He became a gymnast because his mother looked for something to take him off the streets and give an outlet to his Attention Deficit Hyperactivity Disorder (ADHD), diagnosed at the age of seven.
There it is again, sport helping to wean energetic children away from mischief. But kids who get drawn into it to the extent of Jessica Ennis-Hill, Joseph Schooling and Louis Smith do have to cope with something else.
They bypass adolescence.
Smith tried to explain: "I haven't had the chance to act like an idiot before as I've been so busy."
To most of us, being young and foolish is our secret. When sport consumes those adolescent years, there is no room to be idiotic, or normal.