Oh God, You Devil

The following is part of an actual conversation I had while at work today. Twas a conversation about religion, which I should know by now to avoid because I almost always end up pissing people off, but I guess at heart I'd rather piss somebody off than quietly put up with their nonsense - especially when it's not a customer we're talking about. Customers I can usually just ignore unless they're calling me a god-hating babykiller (which has happened before) or somesuch. But I digress.

Person X... see, I'm not totally out to aggravate the world, or else I'd name names. ^_^ Anyway. Take two.

Person X: You atheists are all alike, you refuse to believe in anything that you can't measure.
Me: Oh? How much does a thought weigh? What's the speed of ingenuity? How large is an emotion?
Person X: That's not what I meant. I should have said "anything that you can't prove."
Me: But that's also untrue. I believe there's intelligent life all over the universe, although nobody can prove it. I believe that Einstein was wrong and that the speed of light isn't an unbreakable barrier, and nobody's ever proved that. I don't think anyone's ever proved the existence of true love, either. For that matter, if you want to get really philosophical, we can talk about how it may be impossible for anyone to prove anything aside from their own existence, and that only to themselves...
Person X: Stop being so difficult. You know exactly what I'm saying and you're totally avoiding the subject.
Me: But I'm responding to exactly what you're saying! How is that avoiding the subject?
Person X: I just don't understand why you atheists have to have an explanation or a reason for everything. Why is it so wrong to accept things on faith?
Me: I accept all kinds of things on faith. I mean, it's not like every single piece of human knowledge exists inside of my head. If I didn't take a lot of things on faith, then I could only believe in the things that I've personally experienced. Besides, even if I did know everything that anyone has ever learned - well, for example, science still hasn't fully figured out just why or how gravity works the way it does, but I would still have faith that I'm not going to go randomly careening off into space. And as far as explanations and reasons go, what would you call statements like "God works in mysterious ways" and "because that's what the Bible says?"
Person X: Just forget it. I don't have time for this. *walks off in a huff*

People just slay me.