When he started at Juve and made his name, the coach was Conte, not somebody who would excuse a lack of effort or not following instructions. I don't think Allegri would tolerate much goofing off either. Did very well under both. And Deschamps, another of the same type.
Generally speaking, outside the last 6 months where he absolutely downed tools, I think he was a professional on the pitch at United. He had obvious weaknesses, and so did the team, and it was mostly not a good fit. Not least because there was never a thought, over 4 whole years, to do the obvious and get a DM behind him and CM alongside him, instead playing him behind inferior players like Mkhi/Mata/Lingard/Pereira and finally getting Bruno, an incompatible star signing. From the way his team-mates spoke about him (including demanding ones like Bruno or Ibra) and from what I saw on the pitch, I don't think he matches the caricature of him: virus, lazy, etc.
I don't follow off-pitch stuff much, so a lot of the things that made people angry (the documentary, agent saying things), I found out later. It's funny that the two times his agent opened his mouth before a big match, he delivered a big performance (3-2 vs City, goal and fighting performance off the bench at Leipzig).
From what he showed today, he's done physically. He just gave up on some of the clearances aimed at his head, he'd usually at least fight for that type of ball. Probably scared of another injury.
