I think the simplest way I can describe what bugs me about LeBron is that he presents as a guy who has all the physical gifts you could ask for, who has had things go his way pretty much his whole life, who walks into every game with an advantage over pretty much every other guy on the floor.
Despite all that, he still preens and puffs himself up and bellows and acts like Conan the Barbarian regardless of the size of his accomplishment -- even if it's pounding home an open dunk against a far inferior opponent. He still goes ballistic when calls go against him, even if his team is up 20 points and the series is 3-0 in his favor.
The guy just doesn't have it in him to step back and think, "Hey, you know, maybe I don't need to act like a prince right now. Maybe I can just let my play and my accomplishments speak for me. Maybe this isn't the time to make everything about me."
When things go right for LeBron, there's just an air of well, this is how things are meant to be. Of course I won. That's how the world operates. I can't imagine LeBron ever having a moment like Dirk, who had to leave the court and go to the locker room for a few minutes before meeting with reporters after his team won Game 6 in 2011 because he was so overcome by emotion.