I believe it. I've got friends on both sides of the political aisle. I can't believe some of the stuff my friends think is true, and they think the same of me sometimes.

I think confirmation bias is really strong. We're all best off if we take care to ingest a balance of news. (One of my techniques: I read 'RealClearPolitics' daily. It contains outrageous articles from both sides, which I hope gives me a more balanced perspective.)