Zlatan Ibrahimovic enters this list despite having spent only one season at the club. In hindsight, it should have been evident that a man with as fiery a temperament as Ibrahimovic was always going to have trouble at Barcelona.
He is, after all, never a man to have minced words throughout his career.
Ibra's Barcelona tenure started very well. He scored five goals in his first five matches, and also scored the winning goal in the first Clasico of the season. Around January, he began to fall out of favour with Pep Guardiola's management and began to see less game time.
This coincided with a severe loss of form, including a shocking game against Arsenal where he missed a bucketload of first-half chances.
Ibrahimovic continued to lose form, and in the summer after his Barcelona move, he was shipped off to AC Milan with David Villa coming in as his replacement.
While this seems to be the tale of a typical footballer losing form, the reason Ibra was controversial was the inflammatory speeches that he and his agent, Mino Raiola, made during his time at the club, and continued to make long after he had left.
Ibrahimovic even wrote inflammatory statements about Guardiola and Lionel Messi in his autobiography.
A collection of some of the more insulting quotes made by agent and player:
Why didn’t Cruyff tell Barca that Zlatan wouldn’t fit in before they bought him?
I think that Cruyff and Guardiola should go to a mental hospital and sit quietly while they play cards. They’d be doing a huge favor for Barca. There is a game called Memory that is for kids. It’s a card game where you have to find four cards of the same kind. Guardiola and Cruyff can sit there and play that.
Mino Raiola: “In Barcelona Ibra was going to turn into a zombie. Pep Guardiola did not count on him in anything and so he was back against the wall."
(Pep) was staring at me and I lost it. I thought, "there is my enemy, scratching his bald head." I yelled to him: "You have no balls!" And probably worse things than that.
You are s****ing yourself because of (then Inter manager Jose Mourinho, whose side beat Barca in the Champions League). You can go to hell!