I know this (Susan's) probably isn't the best forum to post on, but I feel more at home here than on some other forums that cater to more specifically atheist viewpoints.
I'm an atheist and have been for, well, over a decade. Which may not seem long, but I'm only 28, so . . . but anyway, it shouldn't happen like this.
I've taken up going to lunch weekly with some co-workers. I usually have a lot of fun and it's good to network.
However, at least one of them is really really religious (missions to China, etc.); which is fine. Whatever. Not my bag, baby. Freedom of religion and ir-religion.
We all got to in the missionary's car for an off-the-clock and off-site lunch and he had some Christian "rock" playing. Someone else in the group, not the missionary person, said, "Well, we're all Christians in this car, right."
I zoned out. Instantly. Before I knew what I was even doing I was gone. Not even there. You could have poked me and I would have maybe, just maybe, grunted. Pure fear and cowardice. You figure: I drive a car with a Darwin fish on it . . . but I still freeze.
Fine, you know, we're at the restaurant, I'm eating some awesome enchiladas, and, as conversations tend to be circular and self-referential, that exact same line came around again. I zone out AGAIN; I stared for about 2 minutes at some blinking Jalapino (sp) pepper Christmas lights. One of them was burnt out.
I feel like I need to tell them that I am not a Christian.
My personal view is that religion is actually harmful to humanity, but I intend to neither persuade them to that point of view or dissuade them from their own as long as they show the same respect to me. If they want an opinion or argument, they'll get it, but I'm surely not going to bring that subject up on my own accord.
Politics and religion are, 9/10 times, not good to talk about at work (or family), even if you agree with the person. I've lost a lot of respect for people because of their stupid and ignorant comments during conversations. Those conversations are what the Internet is for.

And friends, if you have them.
The thing is that this is a really small company, and I know if I tell them, it'll get out. I've just started working there. This area is still red state territory even if I'm in a blue state. While I know they cannot legally fire me for being an atheist, they still may fire me for something pointedly not-relevant. Do I think that will happen? No, do I fear it will? You bet I do.
Atheist and transgendered: two different closets, similar consequences.
Does anyone else just go away when something like that is brought up? It happens to me when someone brings up transgender or sexual orientations, too, but less severely. How am I going to actually come out to the world as genderqueer/androgynous when I cannot even talk about these fundamental parts of my existence? I'm more upset with myself than with my lunch-mates.