Well I've seen cod-atheists asserting that God is impossible. Real atheists never say things like that. I think I know that there's no Loch Ness monster. Of that I'm pretty certain (did you notice the two caveats there?) Even Richard Dawkins says that he can't be absolutely sure that there's no God (as defined by the major religions). If you ask me if I believe in God and I answer no, you've hoodwinked me into allowing the conversation to move firmly on to your territory, and I'm not having it. The best answer is that you're asking me an illegitimate question. So "Do you believe in God?" is a pet peeve of mine!