As a non-Christian, I am NOT offended. The idea that one belief system is right for everyone is insulting. What do you know about my life? Who are you to tell me what beliefs are right for me?

As for Christianity specifically: the Bible was written by human beings, just like every other holy book on the planet. There is absolutely nothing special about the Bible, except for the following: first, it's old; second, lots of people believe it's the word of God. But the same thing is true of the Vedas, or the Lotus Sutra. There is absolutely no reason I should believe that the Bible is more true than any other holy book - and thus quoting the Bible at me isn't going to convince me of anything. It's only going to piss me off. People who stick their noses into your spiritual life and try to tell you how to run your own house deserve to get smacked. Hard.