I find 2 things in sports more appaling than all else: players quitting on their team and players choosing not to play to their potential.
I put these into 2 categories because they are different, as slight as that difference may be. Players that quit once tried hard and succeeded, but no longer see the point of it. A perfect example would be Randy Moss, who quit on his team while he played in Oakland, and has started to show signs of a lax effort with Matt Cassel and the New England Patriots. His reasoning is simple: I'm not going over the middle if there is a good chance the QB cannot hit me in the numbers. Sort of like in "The Wire." Jimmy McNulty is at his best at solving crimes when he is doing the most harm to his body, but he is at his healthiest when he is just walking a beat and is less angry (Really just a great show. Anyone who knows me knows I push this show whenever possible. Honestly, it's one of the greats).
Vince Carter is another example. He tanked it with Toronto, allegedly tipping a play to the Oklahoma City Thunder (low-blow on my part, I admit). After the Nets "traded" for him, he willfully acknowledged that at times he gave less than 100%. He also had the gaul to congratulate Chris Bosh for bringing the Raptors back...after Vince left them in a deep hole. This was done on the court right after Carter's Nets had eliminated the Raptors from the playoffs. Plus the time he got Morris Peterson ejected. And the time he openly laughed and shook his head in disbelief when the Raps fans started chanting "M-V-P" for Bosh. But I digress...
Jaromir Jagr is another player accused of not trying his hardest all the time, partly because he knew that as long as he kept on playing, he would be in line for another $8MM contract.
I'm hesitant to throw Manny Ramirez on this list, just because the Red Sox treated him unfairly so he treated them unfairly.
The other category is of players who never tried their hardest. This includes Vladimir Malakhov and JD Drew. Think of these guys as the anti-Kevin Garnett. The best representation I can think of comes from the movie "Good Will Hunting" (another amazing pop culture reference, if I must say so myself. Coincidentally, one of my top 5 favorite movies) where Ben Affleck's character gets angry with Matt Damon for not living up to his potential: "You've got the winning lottery ticket in your hand, but you're too much of a pussy to cash it in." We see flashes of their brilliance, but they just lack the motivation to give it their all.
I'd much rather cheer for the guys who work their asses off all-game, every game. We (Jays fans) are truly lucky to be able to witness and cheer for Roy Halladay. He really is one of a kind. And other players have commented that his notorious work habits are infectious. AJ Burnett credits Doc quite a bit for becoming the person he has become.
The quitters and the bad Will Huntings are appalling because they are obviously not using all of their talents that they so obviously have. These players could be better than pretty well anyone, but they lack the drive to show how good they can be.