I think it has a little to do with the thickness of your skin. Nothing really bothers me but some of the things I say tend to PO most believers. They act like me not believing in their god is me telling them they are stupid. Brainwashed and ignorant is more like it but I don't say that to them. It's OK though for all of them in the same way telling me I'm going to Hell. If they think I'm going to Hell, they are stupid. But again, I am too polite to tell them that in most cases anyway. If someone were to be actively hostile toward me with the going to Hell BS, I probably would give it to them.

I think it depends on the degree of belief or non belief. I tend to have a high degree of scepticism for non evidence based beliefs. Sometimes I will call out those who may believe in things like ghosts, bigfoot or gods. It leads to some spirited conversation. This can put a strain on certain relationships. Whether work relationships or something more intimate. Don't get me wrong, I know when to keep my mouth shut. But, I enjoy sharing my beliefs while respecting those of others. Relationships are fleeting and are to be learned from. AM I DEEP OR WHAT? Oh how I can go on.

As long as there is maturity and respect, yes. You have to be open to new thoughts and ideas. Rationalize. If it’s unexplainable doesn’t necessarily mean it’s wrong, so then there’s no need to argue about that subject and move on to the next. But if one of the people in the relationship feel their being ripped from what they believe then you have a serious problem.

Why not? I'm seeing someone who is Jewish and I'm an atheist. We're not a couple (At least not yet.), but we still connect pretty well

Yes, with no proselytizing either way. It's probably no much different than
staunch democrat and republicans-- it can work.

Had one with my wife for 27 years even through the death of our son it didn't hurt our relationship.

I would like to say "yes" but in my experience it's not. I'm currently at the end a relationship of more than seven years with someone who clings to an almost fundamentalist faith. Maybe if we lived at a distance from his family but the pressure they put on him hasn't been healthy for us. But perhaps someone else could survive it.

I dated a Mormon for 3 years. She was very religious but never tried to push it on me. Now that I am out of that relationship I would much prefer a non-religious partner.

Do you mean a relationship or a good relationship? The only way for them to have a good relationship is to agree to never discuss religion, but even succeeding in doing that how good of a relationship can you have if topics must always remain off the table?