#9 Cesc Fabregas: Arsenal to Barcelona

Another transfer saga that involved Barcelona and a Premier League club was the Cesc Fabregas saga and that lasted more than just the one transfer window. Having signed him as a teenager from Barcelona, Arsenal had spent years developing the Spanish midfielder before the La Liga club came calling to bring back their prodigal son.
Obviously, Fabregas wanted to return to his former club. They were the arguably the best club in Europe while Arsenal were still struggling to finish in the top four with restricted finances.
The first summer was immediately after the 2010 World Cup where Spain were crowned champions. But at the time, the Gunners refused to sell. Barcelona returned next summer and this time, too, Arsene Wenger refused to let go of a player who was crucial to his formation and style of play.
That was when Fabregas refused to either train with the squad in pre-season or even play as the season got underway. Finally, Wenger gave in and allowed Fabregas to return to the Camp Nou.

To put Fabregas' refusal to train in contrast, Samir Nasri is a more hated figure at Arsenal even though he was far more professional in his final days and played the first couple of fixtures before moving to Manchester City.
Unfortunately, things didn't quite work out for Fabregas at Barcelona.
Also read: To La Liga and back again - The decline of Cesc Fabregas