9. Diego Costa
Few players in world soccer polarize fans like Costa. The Brazilian-born, Spain international is a ferocious presence. Few things please him more than winding up defenders because he is a master of the dark arts. He also had an infamous fallout with former Chelsea manager Antonio Conte.
Costa traveled back to his native Brazil and refused to play for the team. He even threatened to go on strike for a full year because of his poor relationship with the coach. It was incredible drama as the team and fans paid the price for his absence (via Goal).