Complaining about he left is silly. It's like a man crying why his girlfriend who he stole from another man has just left him too.
I really hate it when people use these types of examples to suggest why we shouldn't feel aggrieved. For me, it's an oversimplification than gets rid of the nuances involved.
Everyone expects a very good player to eventually make the move to a top club, and doing it as a youngster of course he'd want to. No-one criticizes a youngster for making a move to a top club.
But what really pisses me off is that he's now gone sideways, or even backwards slightly, when the club who busted their balls to get him, still wanted him and were offering him first team action.
It's okay to make your big move from say MK Dons, but once your get to Manchester United, and they want to keep you, you don't move sideways to a club you never loved, and sideways. I'd be fine if he went to Wigan, or Everton even, if he thought he couldn't make it.
But making 2 big moves in your career, and when there's little to choose between them, despite both clubs wanting you, you stay at the one who busted their ass illegally to sign you.
It's like a random stranger getting picked up by Angelina Jolie, and then after 3-4 years dumping her ass purely because you think Jennifer Aniston looks better, despite there being no problems.
We were his big move. You aren't meant to make a big move, then a lateral move, when both of those big clubs want you. Especially when your reason is playing time, and they are going to loan you (like we might've) /it would be harder to break into Juve's than our midfield.