Atheists... why do you believe that God doesn't exist?

[Neo-Scholastic]

Believer: I believe in God.
Atheist: You're wrong.
Believer: Why am I wrong?
Me: Because there is no proof that your god exists.

-Ahem-

Believer: Here's a logical proof for God's existence:

1) If God (a being who exists in all possible worlds) exists in some possible world, then God exists.

2) God exists in some possible world.

3) Therefore God exists.

Discussions on the burden of proof are often just trifling over nothing. There are definitely times it's useful, but typically only when an argument from ignorance or incredulity is being made. If a theist presents an argument to we atheists (and arguments are evidence), then if we are to be rational in our rejection of (or abstention from, if you prefer) theism, we must have good reason to reject said arguments. In such situations, talk of burden of proof just makes no sense. After all, consider this:

Believer: I believe in God.

Atheist: Why?

Believer: Because the fine-tuning of the universe for life is exponentially more likely on theism than on naturalism, and thus constitutes a strong probabilistic argument for theism. [This does in fact seem to be true]

Atheist: ...You have the burden of proof!

Clearly discussion of the burden of proof because a side issue once the evidence has been presented.

What you say it true for your example. My point is that saying something is wrong, false, or otherwise mistaken shifts the burden of proof. An atheists go beyond simple disbelief once they assert that their denial is the correct position.

But yes. Burden of proof arguments are trivial like you say. At the same time I think its disingenuous for some to rail against believers and hiding behind a facade of indifference. If they were simply nonbelievers then the appropriate position is agnosticism.