In general, I don't discuss my lack of religious belief with many people. They are aware I don't practice any religion, but that is different that them knowing if I believe in a diety or not. The ones that know of my athiesm are pretty relaxed about it. On the other hand, my family is all pretty much agnostic or atheistic. Of course, of the coworkers that know of my skeptism have noticed I respect their beliefs.
When one of my coworkers parent died, I went to the wake with another co-worker. The priest started a small very Catholic prayer during the wake (he explained that during this time, a lot of people start having doubts, and this is to help them reinforce their faith.. all the things that pushed my buttons when it comes to indoctrination about religion).
My co-worker who I went with was a Jehovah Witness, and left the room.I did not, out of respect for my other co-worker. My co-worker noticed. She did share how her skeptism on religion later on (at least organised religion).