What if you're wrong?

I was out with my girlfriend this Sunday. She is a protestant Christian; she is also very liberal and one of the nicest people I know. At any rate, we spoke briefly about religion, and I asked her if she knows the Bible was written by man and many elements of her religion are manmade (well, all of them). She agreed this is true. I then asked if she worries anything in her religion or the Bible is wrong. What if God sits on a cloud and goes, "Why are you doing that?! I didn't want that!" To this, she replied it does worry her.

This got me thinking of the "argument" some apologists use: "What if you're wrong?" This argument, if you can call it that, can be used for anything. It's not simply about the existence or inexistence of the Christian god, but about every aspect of reality. Even if the Christian god does exist, what exactly is he like? What if God doesn't really care whether you worship him or not? What if God is really pro-gay? What if God scratches his head every Sunday, wondering why masses of people gather in buildings that they pretend are important? What if you are doing something wrong, which actually makes God angry, even if you are a Christian?

When it comes to the metaphysical, anyone could be wrong about anything, although many elements of Christianity, if construed literally, are verifiably false, and metaphysical claims are quite ridiculous and unsubstantiated. At any rate, it's not as black and white as just being right or wrong about the Christian god's existence; just think of the countless denominations of Christianity that exist. Even if God exists, who's to say which version is true, or if a true version has even been proposed yet?

If one believes the Bible is divinely inspired, perfect, and literally true, one's beliefs are verifiably untrue. If one believes the Bible was, indeed, written by people and then transcribed and translated, it only makes sense to accept the story was very likely embellished over time, mistakes were probably made, and those who worked on it may have altered the events that transpired to fit their views. In short, those who are opposed to change based on faith are on the wrong side of history; to them, I'd like to ask this: What if you're wrong?