People go funny in the head when talking about politics. The evolutionary reasons for this are so obvious as to be worth belaboring: In the ancestral environment, politics was a matter of life and death. And sex, and wealth, and allies, and reputation... When, today, you get into an argument about whether "we" ought to raise the minimum wage, you're executing adaptations for an ancestral environment where being on the wrong side of the argument could get you killed... Politics is an extension of war by other means. Arguments are soldiers. Once you know which side you're on, you must support all arguments of that side, and attack all arguments that appear to favor the enemy side; otherwise it's like stabbing your soldiers in the back - providing aid and comfort to the enemy.
—Eliezer Yudkowsky, Politics is the Mind-Killer
A sequence on the various ways that politics damages our sanity - including, of course, making it harder to change our minds on political issues.
Closely related to Death Spirals and the Cult Attractor, particularly: