I've told this before, but I know one of the Leafs skating coaches quite well. He says there are SEVERAL players who refuse to work with team officials. He says he sees videos of those players skating with other "personal" coaches and he sees them ignoring their weaknesses all the time. Most of them just want "yes men" who just tell them what they want to hear because they don't want to hear the truth. He also sees all kinds of pros who don't put in the time and effort to get the most out of their abilities. They get into booze, drugs, girls, etc.
He says at the end of the day, it's up to the players and there's only so much he can do. I can't imagine how annoying it must be to hear fans screaming "fire the assistant coaches" when the team isn't having success.
I'm pretty sure this similar experience spans across several different professional sports.