I'm going to give you some advice that runs contrary to what most people are saying:
Don't apologize for being passionate about your beliefs and who you are.
HOWEVER:As a rule, political and religious discussions do not belong at work unless you are an elected politician or theologian =) I know this better than most as a federal government employee; there are opinions you simply do NOT express at work, period. If that means shutting up instead of allowing your core beliefs to be challenged to the point where you must say something, then shut up.
That said, it is perfectly fine to have opinions and, contrary to what the modern student body of most universities seems to think, it is even OK to express opinions that offend people. But, at the end of the day, be sure that you're actually saying what you mean, and you are comfortable with the consequences - and pick your friends accordingly. I have a lot of very good friends that have totally different opinions than I do (one of them told me during the last federal election in Canada that people who voted for the party she knew I voted for were not allowed in her home
), but we express those opinions in a way that ensures we're still going to be friends at the end of the discussion, regardless of what is actually said.
It's fine to have strong beliefs and it's fine to express those (depending on the company), just apply a filter to make sure you do it in a respectful manner. Often it's not what you say that offends people; it's how you say it.
