I know full well how to act in an office. If I talk about personal things, I keep it to networking, technology, and the like. I don't talk about: politics, religion.

Some would argue that politics is of utmost importance - I would agree. Unless I am working with a lobbying firm in a technical capacity, I fail to see how that discussion wouldn't quickly become hostile. And in the end, it also has mostly detrimental effect in poisoning fellow colleagues' communication to you.

If I see or become inadvertently involved in one of those 2 areas, I steer the conversation back to on-topic, or bow out of the conversation. I see no reason to alienate others with my personal practices.