Lionel Messi
Messi is the greatest player of his generation and arguably the best of all time. He achieved a massive amount of success in the early days in Barcelona as he became a club icon. But then the team became increasingly less competitive in European competitions. It enraged Messi that they collapsed every season (via Football Espana).

Meanwhile, the dysfunctional boardroom took him for granted. They mismanaged the team’s financial affairs and Messi refused to take a pay cut. In the end, he walked away as a free agent after spending his entire career in Catalonia. Then he joined PSG after a bitter parting with his former club. It was one of those long-term dramas that didn’t make anyone happy.