kengr

I've found that a good alternative to "None of your business" is "That information is classified on a need-to-know basis." Said with a smile, in a joking tone of voice, it usually gets the point across. And if they continue to press after that, then they will be perceived as being rude.

"I'm not religious" isn't the best possible answer either, but will get you in less trouble (generally) than any of the others. Further comments are usually well-stifled by "That's how I was raised", because then any criticism can be construed as criticism of your parents -- and the kind of person who asks where you attend church has usually been heavily indoctrinated with the notion that you do NOT criticize someone's parents to their face.

I've had some co-workers with whom I was willing to socialize outside the office -- but damned few, and those rarely. I agree that "friendship" should not be an expectation in the workplace.