It comes from me having watched Utd players who fully apply themselves and have a need to perform, Beckham, Keane, G Nev, Ronaldo, Tevez to name but a few. You can see when these players have an inner desire to perform. They left everything on the pitch and gave their all.
Depay doesn't look that bothered, never seems to grab his chance when he plays (aside from playing well a few times against bad teams)! He never seems to fully sprint, never tracks back, his first 5 shots are always wayward to the point of embarrassing, his free kicks are pathetic and wasteful & he never seems that assed.
Comes across to me like the smart kid in school who never really applied himself & will one day regret looking back at having never reached his full potential.... That said, he also strikes me as the kind of guy who'll be happy enough in another lesser league, being a big fish in a small pond,loving a celebrity lifestyle driving his fast cars. I realise there's the George Best "where did it all go wrong" irony here, but for me, he isn't pushing himself for footballing excellence, instead he's striving for celebrity nous.