Obama is making the mistaken assumption that just because people like him, they’ll go along with his policies. Yes, you might be able to change the “tone” of Washington, but the disagreements will always be there.
In the end though, does the tone really matter? House Republicans gushed about Obama after meeting with him about the stimulus plan, then promptly and unanimously voted against it. So unless making sure politicians are polite to one another is for some reason extremely important to you, who really cares about the “tone in Washington?” This is just another example of how naive Obama really is.