What is it about Mitt that makes his Republican rivals hate him so much?

A New York Times article discusses the apparent loathing:

With so much attention recently on the sniping between Senators Hillary Rodham Clinton and Barack Obama on the Democratic side, the almost visceral scorn directed at Mr. Romney by his rivals has been overshadowed…. Mike Huckabee’s pugilistic campaign chairman, Ed Rollins, appeared to stop just short of threatening Mr. Romney with physical violence at one point.

“What I have to do is make sure that my anger with a guy like Romney, whose teeth I want to knock out, doesn’t get in the way of my thought process,” Mr. Rollins said.

The CarpetBagger Report offers the "other guy" theory to explain it. Every time the contest becomes a slugfest between two contenders, Mitt is the bad guy. When McCain moves out as front runner, Mitt's his most credible rival. When Giuliani was anointed the leader last summer, Mitt was the man to beat. And in Iowa, Huckabee saw Mitt as his foe. Even here today-gone tomorrow Fred Thompson saw Mitt as stealing the GOP base. Says CarpetBagger Steven Benen:

For practically an entire year now, the various campaigns have gone up and down, but in every instance, there was Romney, in their face and presenting himself to voters like an ingratiating, toadying Eddie Haskell.

And no one ever liked Eddie Haskell.