Most football fans would have done anything to have been a professional player themselves, so it's often difficult to understand the motivations of players who give up the game when they still have more to give.
When most footballers retire it's because of injury or getting older, but there are a few who chose to end their careers early when they had options to continue. Here are nine footballers who retired when they were still young.
9. Lars Elstrup
Lars Elstrup was part of the victorious Denmark squad, which shocked the football world when they won the 1992 European Championships. Elstrup had also played top-flight football in England for Luton Town.
In 1993 the 30-year old Elstrup suffered from doubts about his football future and quit his club Odense BK to join 'The Wild Goose' religious commune on the island of Funen. Going by the new name of 'Darando', he explained: "I feel that here I am seen for who I really am. They understand me better than I do myself, actually."
Elstrup, (or should we say, Darando) left the sect in 1999, after a controversial incident in which he exposed himself in public and then slapped a young boy. He was later fined 10,000 DKK after threatening one of the sect leaders.
Elstrup had the chance to resume his football career in 2000 when his former club Odense BK persuaded him to make a comeback, but he quit just a week later as he was not guaranteed a place in the first team squad. In 2001, Elstrup hit the headlines again when he defecated in the centre of London's Trafalgar Square.
8. Rory Allen
A product of the Tottenham youth system, Rory Allen broke into the Spurs first team as a teenager and scored against the then high-flying Newcastle and in an FA Cup tie against Manchester United. Allen then had a successful loan spell at Luton, but with first team opportunities at Spurs difficult to come by, he signed for Portsmouth and became their first £1m player.
Allen's spell at Fratton Park was beset by injuries and after two broken legs and eight operations on his ankles, the young striker decided that he would rather walk away from the game than face further surgery. He sent a letter of resignation to the club after failing to turn up for training, which meant that he forfeited the last eight months of his £3000-a-week contract.
Having given up nearly £100,000 in wages, Allen jetted off the watch the 2002-03 Ashes in Australia, where he watched all five test matches. In 2004, the then Weymouth manager Steve Claridge claimed that a man purporting to be Allen requested a trial, only to fail to turn up.
Allen has denied that he attempted to return to the game and claims that he was travelling at the time, stating: "I have never thought about getting back into it. I much prefer playing cricket in the summer and being lazy - in sporting terms - in the winter!" Allen today works in the Foreign Office.
7. Curtis Woodhouse
The career of Curtis Woodhouse started brightly, as the Sheffield United midfielder won four caps for the England under-21 side, but a £1m move to Birmingham City turned sour and Woodhouse began to drift through the lower leagues of English football, with spells at Rotherham, Peterborough, Hull and Grimsby.
At the end of the 2005-06 season Woodhouse retired from the game aged 26, stating that he'd fallen out of love with the game. Perhaps the truth was that he'd fallen in love with another sport, because Woodhouse swapped a football career to become a professional boxer.
Fighting as a light-welterweight, Woodhouse embarked on his first bout in September 2006 against Dean Marcantonio and despite having no amateur experience, won the fight on points. Woodhouse went on to have a decent career in boxing, in which he won the British title. Having made a second sporting retirement, Woodhouse is now back in football as manager of non-league Hull United.
6. Carlos Roa
As the goalkeeper for the Argentinean team, Carlos Roa became a hero at the 1998 World Cup. Roa didn't concede a single goal during the group stages and then made a decisive save in a penalty shoot out to ensure that Argentina eliminated England.
Roa played his club football for the Spanish side Mallorca, though by 1999 it looked as if he would be transferred, with English giants Manchester United and Arsenal both rumoured to be weighing up a bid. Despite this interest, Roa had more pressing concerns on his mind, such as the forthcoming end of the world. Roa was a member of the Seventh day Adventist church and at the age of 29, quit the game to prepare for the apocalypse.
As he explained: "The year 2000 is going to be difficult. In the world, there is war, hunger, plague, much poverty, floods. I can assure you that those people who don't have a spiritual connection with God and the type of life that he wants will be in trouble."
Roa retreated to a desolate ranch in his native Argentina and waited for the day of reckoning. When it proved that the end of the world wasn't as 'nigh' as Roa had first imagined, he returned to Mallorca, where he continued his football career, before moving on to Albacete and Olimpo.
5. David Bentley
Hailed as the new David Beckham, things didn’t work out to plan for David Bentley after his big money move to Spurs.
Signed for £17m, Bentley struggled to continue the fine form he’d shown at Blackburn and eventually lost his place to Aaron Lennon. Loan moves to Birmingham, West Ham, FC Rostov and back to Blackburn followed, without Tottenham or Bentley being able to convince anyone to buy him.
That said, when his contact at Spurs expired in 2013 it was assumed he’d be snapped up pretty quick on a free transfer. Instead, he spent a year without a club before announcing his retirement in 2014 at the age of 29.
Now based in Marbella where he has an interest in a restaurant and several beach clubs, Bentley complained about the state of the modern game, “Now it’s a little bit robotic, the social media side of it, the money that has come into the game. I hate to say it, but it’s made it boring and predictable – calculated – and to go and sign another three or four years into that wasn’t really an option for me.”
4. Hidetoshi Nakata
Another player to retire at 29 was Hidetoshi Nakata. The Japanese legend won 77 caps for his country and spent most of his career in Italy, with spells at Perugia, Roma, Parma and Fiorentina.
In his final season as a footballer, Nakata spent a year on loan at Bolton in the Premier League, but rather than continue his career as a footballer he decided that he would spend his time travelling Japan - a country that he represented but didn’t really know after a career largely spent in Europe in which he’d fallen out out love with football.
“Day after day I realised that football had just become a big business. I could feel that the team were playing just for money and not for the sake of having fun. I always felt that a team was like a big family, but it stopped being like that.”
3. Eric Cantona
At the end of the 1997-97 season, Eric Cantona shocked the sporting world when his announced his retirement from Manchester United and football at the age of 30. In his five years at Old Trafford the enigmatic Frenchman had inspired United to win four Premier League titles, two FA Cups and had been named as the Football Writer's Player of the Year and the PFA Player of the Year.
Though the announcement came as a bolt from the blue, in some ways it was not surprising considering that Cantona was always someone from who you could expect the unexpected. United fans were left to wonder what might have been, had 'King Eric' continued to play on into his thirties, as he was surely capable.
In 2003 Cantona said of his decision: "When you quit football it is not easy, your life becomes difficult. I should know because sometimes I feel I quit too young. I loved the game but I no longer had the passion to go to bed early, not to go out with my friends, not to drink, and not to do a lot of other things, the things I like in life."
Cantona would go on to have a successful acting career and has been on constant work on film and stage since his retirement from football.
2. Peter Knowles
Peter Knowles rose to stardom as a striker for Wolverhampton Wanderers. Scoring 101 goals from just 174 appearances, the brother of the Spurs left-back Cyril also won four caps for the England under-23 side and was tipped to become a full international.
In the summer of 1969, Knowles represented Kansas City in a promotional league played in the USA. He returned to Wolverhampton with more than his full time employers had bargained for. While in Kansas, Knowles had become a Jehovah Witness covert.
At the start of the 1969/70 season, Knowles stated: "I shall continue playing football for the time being but I have lost my ambition. Though I still do my best on the field I need more time to learn about the Bible and may give up football."
The eighth game of that season was a 3-3 draw with Nottingham Forest and was the last that Knowles ever played. Aged just 24 at the time of his retirement, Wolves retained Knowles' playing registration for a further 12 years, in the vain hope that he would one day make a comeback.
The 1991 album Billy Bragg album Don't Try This at Home, included a song called God's Footballer, which told the story of Peter Knowles. The song featured the lyric:
He scored goals on a Saturday
And saved souls on a Sunday
For the Lord says these are the Last Days
Prepare thyself for the Judgement yet to come
1. George Best
When you've won two league titles and a European Cup, as well as being named as the European Footballer of the Year, you might think that there's not a lot more to achieve in the game. That was the case for George Best, who by the early seventies was becoming disillusioned with football and was also pretty occupied with the pursuit of birds and booze.
Following the retirement of Matt Busby, Manchester United went into decline and Best was finding it difficult to combine his off the field antics with his football, as his every move was scutinised by the media that had dubbed him 'The Fifth Beatle'.
In 1972 he announced his retirement from the game aged only 26. The then Manchester United manager Tommy Docherty persuaded him to continue playing, but in 1974 Best gave up top flight football for good. Though Best would continue to play football, most notably in America and at Fulham, he would never again grace the highest echelons of the game in which he had few, if any equals.