Sometimes in sport, the best solution is to quit - to take that self-help book and shove it. To hear the voices telling you that tough times don't last, tough people do… and ignore them.
Because sometimes, when all you've known for 20 years is a narrow-minded existence in a niche sport, and when it's not so much the law of diminishing returns that presides but Murphy's law, the only right answer is one no-one will tell you: give up.
A sporting career, much like a person, is never more appreciated than after its own death, but the difference is only one can come back to life.
David McCarthy can recall with crystal clarity the moment he'd had enough. It was June 2016, and the Waterford athlete was halfway through a 30-minute run - his body drained, his mind distressed - when he slowed to a stop.
"There and then, I knew I didn't want to run anymore," he says. "I walked away from the sport."
He was 27 at the time, and for 20 of those years running defined him. As a teenager, McCarthy was as exciting a talent as Irish athletics had seen, an athlete who could step up to cross country and outlast his peers, then drop down to 800m and blitz them with speed. He had it all.
But when winning becomes routine at such a young age it can heap pressure on shoulders that are ill-equipped to cope.
"You get sucked into this environment being told you're the next big star," says McCarthy.
"But there are people who don't come into the sport until late who become Olympic champions and people who were unbelievable at young ages then fall away and do nothing. I felt like I could deal with failure better than the people around me. Not that they were bothered by it, but I was more bothered by what they would think of me.
"Looking back, the next race was always the biggest race in the world and if it didn't go well it was the biggest disaster - too much short-term goals instead of long-term development."
This, of course, only became obvious in hindsight.
After finishing school at St Augustine's in Dungarvan, McCarthy followed the well-worn path to America by accepting a scholarship at Providence College, Rhode Island, where he progressed well under coach Ray Treacy.
He led the Irish U-23 team to gold at the European Cross Country in 2010, clocked a 3:55 indoor mile in 2012, then came within inches of reaching the world indoor final over 1,500m in 2014.
But McCarthy soon woke up to the reality of life as an Irish-based elite athlete: if you can't do it on your own, you can't do it. He bounced from coach to coach and picked up a stress fracture in his lower back which left him stewing on a couch for three months in 2015.
"I went from worse to worse and I said: f*** this, I need to do it my own way."
There are certain athletes who can coach themselves, who have the desire to work hard and the discipline to hold themselves back, but McCarthy was not one of them.
The week after returning from his stress fracture he racked up 35 miles. The week after that, 65 miles. He then ran more than 100 miles a week for the next seven weeks and it doesn't take an expert in sports medicine to know how that ended - with another stress fracture.
"I had nothing else going on in life so it was very tough, sitting on my hole for another 12 weeks thinking about things."
On New Year's Day 2016 he began a walking programme, but when he finally got back running McCarthy still hadn't learned his lesson.
He started to size up the European Championships that summer and in his first race for more than a year, he clocked a promising 13:42.24 for 5,000m in Belgium, covering the last two laps in a blazing 1:58.
But the problem with his plan was that it didn't exist. Two days later he did an 18-mile run, telling himself to go easy but still averaging under six minutes per mile. Within days he found his energy gauge running on empty, and a few days off did nothing to restore it.
That was how, halfway through that ill-fated 30-minute run, he decided he didn't want to run anymore.
"I walked away from the sport and I never regretted it," he says. "I had the best 18 months of my life."
With the blinkers removed McCarthy began to see there was a life out there beyond athletics
"It was great to wake up knowing I didn't have to run," he said.
"I could have more nights out, enjoy hanging with friends and family more and not feel guilty about it because I had a long run the next morning."
McCarthy knew he wanted to settle back in Waterford so he picked a new career to enable that, starting a post-graduate degree in secondary teaching at Hibernia College.
He ran whenever he felt like it, which was usually a couple of times a week, and joined a CrossFit gym in Dungarvan, finding it a good way to develop all-round athleticism.
A long-time fan of Conor McGregor, he looked beyond the fighter's flaws and marvelled at his devotion.
"Forget what he says or the way he acts, for me it's the commitment to development and everything he'd look at to be a better athlete. It opened my mind to so many areas that help you perform better."
Over the summer, as his father recovered from cancer, McCarthy helped out on the family farm - milking the cows at dawn before heading to the gym, pool or out on the bike for a couple of hours.
He was hired as a fitness coach for the Waterford ladies footballers, with whom he applies much of what he's learned about strength and conditioning.
Content with his new routine, he had no real interest in returning to running, but during mid-term break from his teaching placement he booked a trip to New York to hang out with his friend Kyle Merber, an elite American miler.
They drank beers over Halloween, reminisced about old times and McCarthy joined Merber on his runs each day.
"It was due to be a holiday but it turned into a training camp," he says. "It absolutely kick-started the love for it again."
After returning home he asked Steven Macklin if he would coach him for an attempted comeback, and the Cork man wasn't long accepting.
Over the past month he has taken the reins with McCarthy's thoroughbred talent, nursing him slowly back to fitness with his sights trained on the long-term view.
"Steve's not only a great coach but a great friend," says McCarthy.
"I realised I need a coach, I need guidance and someone to put me under control."
McCarthy currently runs about 60 miles a week, but puts in another five hours a week swimming or in the gym, where he's overseen by strength and conditioning coach Kenny Murphy.
He plans to start racing again soon but they'll be low-key outings with unspectacular results - small steps on the path to somewhere better.
This month he returns to St Augustine's for his final 10-week teaching placement, and throughout that running has a place - just maybe not the all-encompassing centrepiece it occupied before.
"You can do all these other things and still be a very successful athlete," says McCarthy. "There's a lot of hours in the day and a lot are spent overthinking things, at least they were for me. But I left the sport 18 months ago and realised I can live perfectly fine without running. In fact I was happier than ever."
Secure in that knowledge, McCarthy is ready to bring his career back from the dead. At 29, he knows there are many years left to show the permanency of his class.
"My body is so healthy and strong and I feel better than ever," he says. "I'm on it this time. It's going to be good."