They're still human beings before they're republicans or democrats. I expect them to behave in a manner that says they're putting the nation first, not one that says "boo hoo, you don't agree about my pet projects and issues." There is a lack of mature, even-tempered discourse in Congress that wouldn't fly in a grade school.
I do wholeheartedly agree with your first paragraph, though.
Nation? Politicians are elected to represent their constituents, and not the nation. Factionalism is a key component of the American system. They are supposed to fight for their state and not for America as a whole. In that light, having a politician say that another is 'boring' is perfectly natural.
I do wholeheartedly agree with your first paragraph, though.