Religion is optional, totally!
I concur, and I choose my friends wisely. That doesn't mean we can't be kind or appreciative of acquaintances or strangers. For chi chat, there are lots of topics besides religion and politics.
Yes, and luckily, I'm able to get along quite well with people and have great interactions, but I mainly avoid people, and I never feel like I can really express to them my true beliefs or ideas too vocally or clearly for fear of being utterly rejected or exposing the major differences in our ideologies and worldviews as expected, since I highly doubt (even if they claim they believe in God), that their God and my God's qualities and activities are anywhere near the same.
Harboring this thought, that they aren't really like me, they don't see what I see, know what I know, creates a kind of slight barrier, even if I'm smiling and speaking lovingly and kindly to them on all manner of topics, my religion really is my whole person, and their not being able to know it, is their not being able to know me really.
This is my feeling with the religious and the non-religious alike, and so I feel detached and alienated and hidden from most people, and its sort of unpleasant and uncomfortable, and seemingly can't be helped.