The first thing to know is where we are coming from. As atheists, we do not believe the Bible or Qu'ran has any particular merit or credibility on statements of truth, any more than a random book of fiction plucked off a bookshelf.

If we are engaging you, as a holy book-endorsing person, in discussion, there's a level of seriousness already at play. We think these topics are important, and so do you.

Suppose the atheist was countering your arguments for the existence of a god by referencing a napkin that has "God is not real" written on it. Clearly, you wouldn't see this as a valid source of information.

You give a Cosmological Argument, and the atheist responds, "But the napkin says God is not real."

You give evidence for the efficacy of prayer, and the atheist responds, "But the napkin says God is not real."

You give testimonial evidence of people who had personal experiences, and the atheist responds, "But the napkin says God is not real."

... wouldn't you get annoyed after awhile, too? It seems the other person does not even even bother to try to have a serious conversation, and so you're basically wasting your time.

After a few hundred of these types of discussions, don't you think you'd have little patience for the "napkin defense", from the onset of the discussion?

That is how we see Bible quotes. The Bible's claims are basically what you're trying to demonstrate as true, so the Bible can't be used to demonstrate that they are true. It is one thing to have a discussion about the nuances of Christian or Islamic doctrine, but we are looking for independent corroborations to the claims... not unceasing tedious monotonous references to the book you're trying to prove.