I am very open about the fact that I'm an Atheist.I am Assertive/borderline aggressive. I grew up in an aggressive environment so I do not fear threats. I do not back down when challenged on the subject by ANYONE, immediate family & friends included. Example.
I have a very close circle or friends in my current location who I have known since I was 14. As I stated above I am very open about it, but I have been really lucky that none of my close friends have taken offence to my recent "coming out"... Or so I thought. The closest one to me out of the group decides (not even an hour ago) to ERUPT!!!!! Now mind you this guy can kick my ass up and down the street, and I grew up fighting so I can hold my own. So even as my calm, neutral (in my opinion) questions sent him into what I am going to nicely say was a "physically aggressive" posture. I never backed down. I made my points, and in his blind almost rage... He agreed to pretty much all of my points, but is so blinded by jesus he didn't realize it.
NEVER BACK DOWN.