Assume there really is a god of some sort. What happens to an atheist on judgment day? Two takes:
The simple fact is that the “God” of the Bible is so absurd and so self-contradictory that his existence is an impossibility. The idea that any other “god” could exist in its place, and allow such absurdity to infect and delude so many, means that any other god is an absurdity as well, and thus equally impossible. Thus, God is imaginary – any god.