It seems nothing can ever go too smooth for too long when Jose Mourinho is at the helm.
The Special One has never spent more than three seasons at one club in his managerial career and it doesn't look like he intends on staying beyond his current three-year contract at United, either.
The Red Devils boss has openly attacked his critics recently and seems fed up with those who don't like his counter-attacking tactics against fellow big sides.
Furthermore, back in October, the former Chelsea manager lauded French heavyweights Paris Saint-Germain.
“The other day my son, who lives in London, went to Paris and not to Manchester to watch the match,” Mourinho said. Asked why his son chose that option, the United manager added: “Because at the moment in Paris there is something special. Magic, quality, youth, it’s fantastic.”
Why he felt the need to state that is anyone's guess, but ever since his comments the rumours surrounding the Portuguese tactician and PSG have refused to die down.
According to The Sun, Mourinho will actively seek a move to the French capital at the end of the season if the Parisians decide to part ways with Unai Emery.
If the Spaniard fails to capture the Champions League, it is believed PSG have Mourinho at the top of their wishlist and Mourinho has another reason he would like to escape England.
The same report suggests that Mourinho doesn't believe that United can compete with local rivals Manchester City this season or in the future.
Pep Guardiola's side have looked unstoppable this season and are still unbeaten at the top of the Premier League, but they have made huge investments to get the squad to where it is.
Mourinho wants the same kind of cash and despite breaking the world record for Paul Pogba during his first summer with the club, he was frustrated when told he had to sell someone before bringing in Ivan Perisic last summer, which he ultimately opted not to do.
Of course, at PSG there wouldn't be any financial restrictions for Mourinho and France boss Didier Deschamps could see it happening.
"Jose Mourinho, why not?' said the former Juventus midfielder. 'He's pretty happy at Manchester United at the moment. But he's a bit of a globetrotter. So why not in France too? He has not been to France yet.
"PSG are the most stand-out team in France. They are doing well nationally and in the Champions League."