Some players will do great things for one club and have fans scratching their head at another.
There are many reasons for players to succeed or fail in football, and many can't be explained.
Take a look at four players who didn't live up to their reputation, players who were big fish in small ponds but failed to stay a float in a sea of talent.
4) Demba Ba
To be fair to Demba Ba, he has done remarkably well to end up at one of the biggest clubs in the world, Chelsea.
The French-born Senegal international had to fight to win a professional football contract after receiving rejections from clubs such as Watford, Swansea and Gillingham as a teenager.
He was given his chance to shine in Germany when 1899 Hoffenheim signed the striker for the 2007/08 Bundesliga 2 campaign.
Ba impressed during his four seasons in Germany, scoring 37 league goals in 97 appearances, but was known for his injuries.
When Premier League side Stoke City ended their pursuit of the forward at the last minute in 2011 it looked like the future was bleak for Ba.
His fortunes changed when West Ham took a chance on him, and he repaid them with seven goals in 12 games – but it was not enough to prevent their relegation from the Premier League.
His goals didn’t go unnoticed though, and Ba was snapped by Newcastle during the 2012 summer window.
At the time Newcastle were a side with limited ability and Ba came into the club as their main hope.
He took to his role as number one striker and scored 29 league goals in 54 games.
He took the chance to sign for former European champions Chelsea last year and has since disappeared into the Blues’ mist.
Opportunities have been limited and Ba would be much better off as the main man at a top-flight side rather one of five stars competing for a starting spot at Stamford Bridge.
3) Michael Owen
Owen was a fantastic player at Liverpool and was not the only star in their side.
But the reason for his inclusion has to be his massive fail at Real Madrid.
Signing for the best team in the world at the time was a chance the England man couldn’t turn down.
But he was leaving a guaranteed starting-role and hero status at Liverpool to join a side where he would be lucky to get a look in.
At the time of the ‘Galaticos’ Madrid had Luis Figo, Brazilian striker Ronaldo and French legend Zinedine Zidane to name a few in their ranks.
Owen wasn’t able to make a name for himself as a hero at Madrid despite scoring goals.
He was sold to Newcastle United in 2005 for £17 million and was welcomed back to the Premier League like a god with a Bernabeu style presentation in front of thousands of Toon fans at St. James’ park.
There is no doubt Owen was one the best strikers of his time, but his failed Spanish adventure meant the player missed what was perhaps the best years of his career.
2) Alex Song
Alex Song’s transfer to Barcelona was one of the most surprising moves in the 2012 summer window.
Despite showing his potential in the centre of the Arsenal midfield it was hard to see where the Cameroon international would fit in the Barca pack.
Arsenal snapped up a 17-year-old Song in 2005 after he impressed at French side Bastia.
But it wasn’t until the 2008/09 season the nephew of former Liverpool defender Rigobert Song really made an impact for the Gunners.
After four seasons as a regular in the Arsenal first team he made the £15 million move to Spanish giants Barcelona, and almost immediately saw his career halt.
Despite 20 league appearances for the Catalan side, the 26-year-old was largely unimpressive and has been linked with a loan move back to his former London club.
Song is another player who is seemingly unable to adapt to this surroundings and would be much more suited proving the doubters wrong elsewhere.
1) Ashley Young
There was a time when Ashley Young looked like he was going to be the next superstar for both Manchester United and England.
Full of confidence fresh from a move from Aston Villa, the tricky winger was showing everyone why Sir Alex Ferguson paid £20 million for his services.
But it didn’t last long with the 28–year-old as he slipped out of the United first team and had to settle for cameo roles.
He has since lost his place in the England squad and shown more diving ability than Tom Daley.
Being the star man at Watford and Villa clearly suited the London-born midfielder and perhaps he will regain his form and international status at another club with less pressure attached to them.