Neymar, Pogba and Hazard are perfect example of how a single move can ruin your career - Where you're King? Stay King.
Just because the move didn't turned out well form doesn't mean they made the wrong decisions, Neymar was already a king a Santos before coming to Barcelona, If Ronaldo had stayed back at Manchester United do you think he would have achieved half of what did with Real Madrid, should Mo Salah have stayed back at AS Roma because he was already one of the best in Serie A then ?
Lewandoski and Marco Reus were a duo-king in Dortmund back then, but Lewandoski moved to Bayern Munich and what would you about both players carrier after Lewandoski moved to Bayern, and Reus couldn't complete his away from Dortmund as well, who carrier had been more progressive after that split ? Suarez also was a king in Liverpool in the Suarez, Sturridge and Sterling partnership but did his career retrogress upon switching to Barcelona ? I could keep on mentioning names, of players the left a club because they needed a better shot at being the best in world or playing for a bigger at least for their brand and image right increment and probably a larger exposure or more attention, after all it's usual just business for the club when you become aged and almost can't give your 100% any more they begin to you uttermost less respect and priority, so I'm with a player who make move which they believe would be step up to their career and brand as a whole, because after their football career that'd be all they have left, I'll end my statement with an infamous quote that goes thus,
"If you can drink from the fountain, why then, should you request for a drink of water from the cup?".