I have lots of friends, family and co workers who are religious. They are nice people who I like but I try to avoid telling them I'm agnostic. I just don't want to ruin the relationship we have or want them to think differently about me. I guess if they are true friends it won't matter but I still avoid telling.
I don’t “advertise” it in my day to day life. I work in healthcare, and there are a lot of very religious people I deal with every day. My close friends know my stance. I don’t display any bumper stickers on my car or anything like that. It’s just not my style to shove my beliefs in anyone’s face, like a lot of religious people do.
The only time it really comes up is at work whenever there is a holiday coming up. I always ask my kids if they celebrate the holiday if there is a craft or seasonal activity. They often ask me if I celebrate or go to church. My policy is to be as honest as the kiddo is able to understand.
In my experience, people who have grown up with religion are very live and let live. The militant believers have usually converted after having done something they're ashamed of and need to believe that they've only gotten forgiveness and a clean slate due to their acceptance of an all powerful Jesus Christ.
99% of the time it isn't an issue here. Religion isn't often a topic unless there has been a news report about a religious nutter somewhere, then we just take the piss.
Occasionally come across believers and have no problem explaining why I am an atheist if the need arises.
I would prefer that people get to know me first so they won't immediately judge me. I am in Texas so I am surrounded by religious people and so far all of them know because it always comes up. Things like "what church?" "do you go to church?" or "would you like to join me at my church?" or other comments always lead to "I'm an atheist". I'm not ashamed of it at all. I would wear a shirt that says "I'm an atheist" if I could find one. It does seem however that everyone I tell that is religious has to tell everyone "she's an atheist!". I just sometimes want to say "she's a sheep!" but I keep my mouth shut about it. To each their own.
I voted I tell people, but I want to clarify that I don't preach it. I often wear T-shirts saying things like "Science doesn't care what you believe," "I don't pray for things to happen I just get things done," "Skeptic," "Logic," and a few others. If I'm asked I will tell them I'm an Atheist, but I don't believe in mocking people for their beliefs.
While my vote was 'Tell People', it must be expounded upon just a bit. I will not hesitate to tell people my position, but I won't do so without reason. That is to say, if someone questions me directly or the path of a conversation leads to it, I don't hold anything back. Likewise, any commentary on my part is tempered by the tone and specific topic. I can get downright militant as well when the situation warrants it.
I am antitheist, but I don't walk down the street pummeling each and every believer type person I come upon. That would be far too tiring and counterproductive. Alienating people is not how one gains any ground.