This certainly doesn't surprise me regarding his contempt for Mittens. It was palpable all the way back in '08 when he just couldn't resist publicly making fun of Romney even when his odds of becoming the GOP nominee were obviously small.
http://www.youtube.com/watch?v=080zoBmb7eQ
http://www.youtube.com/watch?v=emiOx7-hetQ
It seems like most or all of Romney's political opponents feel the same way. He immediately and transparently comes across an entitled empty suit who stands for nothing and is only in politics in order to add some other notch to his belt.
They all feel like they had to fight on the power of their personalities and convictions to get where they are in politics while Willard (lacking both aforementioned qualities) simply bought his way to the top with his wealth and daddy's connections.
I'm sure many, or even most politicians, have the same sort of petty motivations for entering politics, but Romney is just laughably terrible at hiding it.
Some people say that Obama wanted to be president before he was ready, and ran on speeches and catch phrases, without really having a record of any successes.
Obama has said that he didn't realize the amount of work and daily tediousness that the job of the presidency required. He didn't realize the importance of daily messaging, and that contributed to the huge backlash in 2010.
