My experience is that there's rarely a time that is appropriate for it to come up in polite conversation. People talk about it all the time within their social communities as the social communities are more likely to be in line with their beliefs, but not really in "public" IE work, etc. The guy running around talking about "god is dead" at work is just as much of a jerk and treated as such as someone who loudly proclaims their christian beliefs as the basis for everything they do.
The two things go hand in hand. People strike a more defiant attitude when they anticipate punishment. They can seem clueless and overly confrontational when they cop that attitude in a context where it isn't warranted.
Also, religion comes up routinely, though perhaps not frequently, in contexts where religious belief is assumed. In an ordinary conversation about the right way to handle a situation, people will ask you, "Do you think God wants me to ______?" It's just a manner of speaking, but it forces you to either pretend belief or out yourself and face their judgment. It's only in "mixed company" where people avoid the topic.
