#3 Confusing tactics
Several times this season United have gone on a run of winning games and just when you think that they've turned a corner, they suffer another embarrassing defeat. A perfect example of this is how impressive wins against Liverpool, Chelsea and Crystal Palace were followed by a poor defeat to Sevilla.
Again Mourinho has to take some of the blame for this. In the wins against Liverpool, Chelsea and Crystal Palace United were at their best when they were on the front foot, playing an aggressive, attacking style of football. Yet bizarrely Mourinho chose to revert to a more defensive style of football against Sevilla and paid the price for it.
If this was a one-off bad performance, it wouldn't matter so much. Unfortunately for United fans, we've seen plenty of terrible performances this season ie vs. Man City, Chelsea, Bristol City, Huddersfield Town, Southampton, Burnley, Basel, Leicester to name just a few.
With Mourinho adopting such a defensive style of football this has blunted the promise of players such as Marcus Rashford and this could lead to his departure.