Regarding the differences between repubs & democrats I've always wondered if our brains were wired differently. There are some personality tests that are often used to help young folks chose a career. According to this article, the same tests also indicate whether you'll be center left or center right.
center right tend to be conscientous but not open to new things
center left, not very conscientous, but open to new things.
Personality and Politics: New Evidence from Germany, Bryan Caplan | EconLog | Library of Economics and Liberty
This may also explain some of the frustration the two sides have talking to each other. The right trys to argue using a set of rules to debate by, while the left aren't bound by such rules and kind of bounce all over the place without the constraints of rules and/or evidence.