6. Carlos Tevez vs Roberto Mancini
During a Champions League tie against Bayern Munich in 2011, the Argentine forward decided that he would rather stay on the bench than get on the pitch in what turned out to be a 2-0 defeat for the Citizens. This left Mancini fuming, and he declared that Tevez was finished at the club. He disappeared back to Argentina with telling the club, and was only allowed back after crunch talks between the two had taken place.