If you do find yourself in the middle of a religious discussion, stay light-hearted about it all. Remember that God invented humor, and it helps keep you from getting personal. This is a discussion about beliefs, and not about individuals. In the end, you can always agree to disagree, and remain friends. You might end up meeting a kind Satanist, or a mean White-Lighter.
Diversity is a wonderful thing.
The chances that in a period of ten minutes you are going to stumble upon the key to all knowledge of God is slim to none. You're in a discussion to open your mind and the minds of others, not to prove you're right. It's about strengthening your beliefs, not changing the beliefs of others. They are just as stereotyping and offensive as getting personal. Some people don't want to open up their minds.