I've been an atheist for quite a few years now (probably 10) but I grew up in the south and started life as a Southern Baptist. I'm sure you all know what THAT means: fundamentalism.
Today, I had a startling realization: In all those years as a fundamentalist Christian, I was always shy about talking about "my faith", talking about Jesus, or saying those things that Christians routinely say to each other -- things like "praise the lord", "god is great", etc. I was still a practicing christian, mind you, and I went to church every Sunday, but I could never talk about it without great discomfort. (In contrast, I've never been shy about saying other provocative things, or espousing opinions that go against the opinions of all my friends. I've always been a bit of a gadfly.)
I realized today that deep down, I must have known that it (religion) was absurd. I was embarrassed because those beliefs are embarrassing. But I was so brainwashed, I couldn't think objectively about them.
Now that I'm a non-believer, I'm happy to talk atheism to anyone without embarrassment (and it's not always a welcomed topic). In fact, I have what one might call an 'evangelical' zeal about it.