#2 Paul Pogba
Perhaps this is what annoyed Mourinho; perhaps there is something else behind the scenes we don't know about. Too often, though, the Frenchman has played like an individual not interested in helping his manager or team. He has still, admittedly, contributed 2 goals and 2 assists but hasn't dominated games in the way he is capable of.
Although Pogba has certainly seen a lot of first-team action this season, being an ever-present, Mourinho still doesn't seem to trust his midfielder. They have been in constant opposition since the summer, when there was much-talk of Pogba departing for Barcelona.
Pogba played the best football of his career under Massimiliano Allegri at Juventus, where he enjoyed the trust of his manager and adhered to his tactical system. If Mourinho could communicate more effectively with his player, instead of openly ostracising him, there's no question that Pogba's performances will improve as a result.