Chris Christie may harbor dreams of winning the presidency in 2016, and for the last few years he has done a moderately good job acquitting himself. Sure, he's got the persona of a bully, but in New Jersey that's a positive trait if you want to get things done. Christie has gotten many things done. However, his road to the White House is starting to his some snags.

For the record, I have no issues with Christie calling a reporter an "idiot". Most of them are idiots. Unfortunately, they are the heralds of his public personality. It would help if he managed his tongue a bit.
That said, you don't have to go very far back to begin to see where he started going off the rails. Perhaps the first indication was his speech at the Republican convention in 2012, which was a decent enough speech, but all about Christie. This didn't win him any friends. Then came Superstorm Sandy and the appearance of ditching Romney and cozying up to Obama. That was him playing the political reality and doing it as well as he could. It's hard to fault him for trying to make sure the citizens impacted by the storm weren't ignored by a president who ignores anything and anybody Republican. However, it did not win him many friends in the party mainly because of the timing.
Lately, things have gotten more difficult for Christie. Among his most recent issues were the attempt to undermine NJ Minority Leader Tom Kean, Jr. (who just happens to be my state representative and doesn't live too far from my house - very nice guy). Christie's coattails in the last election were very poor. It's rare that a governor wins with such a large margin and doesn't drag a few state Republicans into the legislative branch with him. In order to hone his 'bipartisan' image, Christie didn't do much stumping for NJ Republicans, in what seems to be a wink and a nod to the NJ Majority leader and state Democrats. He took this a step further and actively pushed for a replacement to Tom Kean, Jr as minority leader. This was an unprecendented involvement by the NJ executive in legislative affairs, and not well received.
To make matters worse, Christie is now involved in a minor imbroglio in Fort Lee, where one of his appointees traded emails with his chief-of-staff regarding the creation of traffic snarls at the George Washington Bridge. Christie isn't clearly involved, but his fingerprints are all over what appears to be an attempt at pay back for the lack of support from the Democratic Mayor of Fort Lee.
As a Libertarian, I run hot and cold on Christie. I respect his (quite substantial for NJ politics) accomplishments, but his ambition has exposed his worst side. Sure, he's a bully. That bully persona, however, is becoming who he is rather than remaining a useful tool in his kit, as it had been early in his tenure. He is inserting himself in places he does not belong, a fatal flaw of the current Chief Executive. If he really wants to be president, he would be well served to do his job, avoid causing trouble, and keep a lower profile for the next year and a half. I don't think Christie is a great potential candidate. Better than many others, perhaps, yet still terribly flawed.
Yet that is the trouble with politics. Perfect candidates are non-existent, and this is the primary reason smaller government is better government.