To make it to the highest levels of professional sport you need a very particular set of mental skills.
Single-mindedness is one. The ability to use any slight against you to motivate yourself is another, one which was showcased in the recent ESPN Michael Jordan documentary, The Last Dance.
The former Chicago Bull superstar gave numerous examples of how he would turn even the slightest diss into an all-consuming rage which in order to fuel his performance next time he went out on the court.
It's no different in football, an industry where plenty of players have grudges against former clubs or individuals.
Coming a day after the 45th anniversary of one of the most heartbreaking evenings in Leeds United's history, when a dreadful refereeing performance cost them a European Cup win, one of that season's bit-part players has had his say on the grudge he continues to bear, four-and-a-half decades on.
John McGovern was signed up before the infamous 1974-75 season, when new Whites boss Brian Clough paid his former side Derby County £125,000 the Scot and John O'Hare.
Clough's 44-day spell in charge at Elland Road is one of the most well-documented managerial spells in English football history, with McGovern's short spell largely a mere footnote in the saga.
With Billy Bremner and Johnny Giles blocking his path to the starting XI, McGovern played just four times for Leeds, being jettisoned from the squad after Clough's exit.
He would be reunited with Clough at Nottingham Forest in January 1975, but his six-months in West Yorkshire left a scar that he still revisits today.
"If the Leeds players hadn't been so successful under Don Revie, they might have been willing to give the new manager a chance," he told The Sun.
"But from day one there I knew it was a bad move for us, the way they treated me was disgraceful.
"I got booed when I ran on to the pitch to make my debut.
"I was sold hospital balls by team-mates who'd slow down when I passed to them so it would go into touch and make me look bad.
"It wasn't just the football staff. It went right through the club and I still don't know if they'd all been told to treat me that way."
While Leeds came agonisingly close to a first European title at the end of that season, McGovern would go on to lift the European Cup twice during his spell at the City Ground and he still to this day likes to rub salt into that particular wound.
"What goes around comes around and Leeds never won the European Cup and I won it twice. So take that. Every time I go back to Leeds United I wear my European Cup winners' tie. And I make sure everybody sees it."
