The simple answer to offer is that it's the manager. Ole Gunnar Solskjaer. A different personality. With different expectations. And significantly one familiar with what makes Pogba tick after their time together as coach and youth teamer a decade ago.
But this rebuild runs much deeper than the differing natures of Solskjaer and the man he replaced, Jose Mourinho. By his own admission, Solskjaer has insisted there's been no crunch talks. No deep, one-on-one chats. This hasn't been about getting inside Pogba's head. Where the change has occurred is on the pitch. This snappy, up-tempo way of playing - something which Solskjaer has insisted upon from the first day.
He has his own approach, sure. But the Solskjaer Way tips a hat to the methods of his one and only manager as a United player.
During Sir Alex Ferguson's time in charge there was a mantra. From the first team down to the U8's. A demand from the top man at the club. 'That third pass must go forward'. It didn't matter if you were a junior or a Champions League winner. This was the playing culture under Ferguson. 'The third pass must go forward'.
And this approach - after a hiatus of five years - is back. And to the benefit of United's No6.
United still play through Pogba. As they did under Mourinho. But the difference now is what he sees when he gets his head up. And also, what his teammates expect - even demand - from him when he's in possession.
The dithering Pogba. The one who would get caught on the ball. Try one trick too many. That Pogba is gone. Not by any mental ploys from his manager. Not even by the player, himself, consciously making the change. This has come from those around him. His teammates. Particularly those in attack.
In this system. At this pace. There's just no time for Pogba to sit on the ball. To look left. Then right. Then left again before knocking it sideways. Not when he can only see the backs of Marcus Rashford and Anthony Martial motoring away from him. Not when they're angling forward runs in one direction. Then another. All to get free for Pogba to find them with a pass. The days of playing it to Romelu Lukaku's feet. Getting it back. Then starting again... are over. It's now forward. Everything's forward. And at pace. "Blistering" (as the manager says) pace. There's just no room for a player - even a £95m one - to sit on the ball a split second too long. He'd be just letting everyone down.
But what of the attitude adjustment? The personality change? From the recalcitrant to the ready and willing team player? It was significant that Solskjaer was eager to volunteer last week that Pogba had snubbed an invite to the Brit Awards. In contrast, Daniel Sturridge - who would get on the pitch for Liverpool on Sunday - did make it to present an award.
Eric Cantona, Solskjaer's former teammate, put forward over the weekend the one big change he had seen in his fellow Frenchman.
"Since Ole has arrived, he hasn't changed his haircut," said United's famous No7. "Maybe he made Pogba understand that the priority is to play football.
"First you have to be good on the pitch, and then you can do something else. If you lose your concentration because you're thinking more about your haircut than your football, that's not good."
Cantona just about captures it. But this column would argue the haircuts. The social media. The overall antics we saw from Pogba last year have been shelved simply because he's happier in his job.
Under Mourinho. As United lurched through the season. Football had become a job for Pogba. A chore. And his escape was social media. His appearance. His haircuts. That was where he was getting his enjoyment. His escape.
Today, that lifestyle has been flipped on it's head. Now it's a joy to go into work every day. To mix with his teammates. With his manager and the coaching staff. There's no need for an escape. For a respite. United and Carrington are giving everything that Pogba needs.
As Solskjaer has stated, he knows what makes the midfielder tick. This isn't Roy Keane. Nor Paul Ince. He doesn't play his best when wound up. Angry.
“I remember when he was 16 he wanted to feel good," Solskjaer recalled. "If you feel good, you will play well."
Which is just what we're seeing now from Paul Pogba - on and off the pitch.