It may be a surprise to some to learn that I once considered myself a conservative. I come from a conservative family. Growing up, Ronald Reagan was our hero. I was too young to understand anything about politics, but I had a great childhood and I had confidence in my parents and there reasoning (I still do actually, my mother is racing to the left at the moment). I continued on my conservative bent on through college; fighting off the revelations of reason I was receiving. As we got into the thick of the Bush administration, and I began to lose arguments badly, I backed off a bit and changed my views to "moderate, with right leanings". This was really the beginning of the end for my life as a conservative.
I fought the good fight, but at the end of the day, none of the ammunition that I was provided with by right wing ideology was doing the trick. Those who I was debating held the high ground on almost every issue. I began to realize that things I was arguing for weren't convincing me either. When faced with that kind of cognitive dissonance it seems that the only options that one has are to change your mind about some things or plug your ears and double down.
Ironically, it was a theology professor of mine who told me that an extremist is someone who when they get lost, drives faster. I am not sure where he got the quote, but it stuck with me, and has always reminded me that we cannot be afraid to change our minds when the facts don't match our world view. And that is really why I have become the godless liberal I am today, no matter how I tried, I couldn't make reality fit the image I had had of it.