Gaming is a wonderful hobby that can let us leave the stress of our everyday lives behind. It is a great escape, and a means of keeping many of us sane. And it turns out lots of us have similar interests, so babbling about Star Wars, Doctor Who, or even pro wrestling doesn't sound nearly as strange as it does in our day to day lives.
You know what doesn't help people relax? Talking about religion or politics. I'm not talking about the occasional joke or one liner. I'm talking about protracted discussions about religion and politics. People's feelings about these topics run deep, and can be pretty involved.
All I'm saying is that some topics can be sensitive, and while you never know what might trip someone's trigger, if you want to make an educated guess, most of the hot button issues probably reside under the topics of religion and politics.