There was another reason as well: "atheist" tends to be viewed as equivalent to loose morals and every possible bad habit that one can imagine. Whereas my life is far from that, as a non-smoking teetotaler who doesn't even know the smell of marijuana, and gluttony or sloth or greed are not what I practice either. So, it took me a while to overcome the concern that my atheism might project me as somebody that I am not.
But, then quite a few years ago, I emerged from the religion closet, and ditched my "agnostic" label in favor of a more open "atheist" one. And, liberating it has been since!
It was a wonderful coincidence that soon after began the huge wave of bestselling books on religion and atheism. There is no doubt that Christopher Hitchens and Sam Harris, among others, significantly elevated societal discussions on religion and god. Though, I did worry that Hitchens' personal life could reinforce the negative stereotype of an atheist.
As Harris and Steven Weinberg and many others have pointed out, life is a lot more fascinating and rich and complex and human when moral guidelines have to developed and practiced devoid of religious prescriptions. It turns out that living a life of an atheist is way more wonderful than I could have ever imagined.
Further, it turns out that people become naturally curious even if I were to mention merely in passing that I am an atheist. They want to know more about my atheism--perhaps because of doubts they have about their own religious beliefs, or because they have never interacted, in-person, with an atheist, or ... I am more than happy then to engage in conversations with them.
From a strictly scientific perspective, I suppose I would clarify that my working hypothesis is that there is no such thing as a creator or a god. After all, I don't have conclusive evidence. But, if I were to remove those scientific qualifiers, then it is simply that I am an atheist.
If all these are too serious, then, hey, we can always lighten things up .... like so:
Here is Colbert explaining religion--Christianity
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