The universe is immense. The only tiny spot we know that can sustain life is on Earth. Our existence spans a minuscule fraction of the time Earth will have been around before it gets destroyed by the Sun. If the preposterously small probability of life appearing by chance needs to be demonstrated, we are the living proof.
And even then, we're not all that wonderful. Our "superior" intelligence often remains questionable. We're not even necessarily going to evolve "towards the better" since that would require, according to natural selection, smart people to make more babies than people with lower IQ, for an infinite period of time. Perhaps we're even nearing a peak in terms of global human intelligence.
Considering how the entire universe is filled with chaos and how we're doomed to disappear eventually, how is our absurdly lucky and miserable existence in this universe supposed to serve as evidence for design? The more you look around us, the further you manage to reach out and explore, the more you see how it's actually quite probable that life would happen once in this big mess of colliding galaxies and dying stars.
If some gods really created this chaotic and lifeless universe around us, just to put life on 0.00000000000001% of it, and for such a silly amount of time. If they supposedly did it for us to better enjoy their own supernatural dimension after we die, they're not very skilled at this "creation" stuff. They should quit.
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Most creationist arguments do not describe atheism properly. Atheism simply involves not believing in a god. It's not even something that needs to proven. It's not an ideology. It's not a belief. Neither is it incompatible with agnosticism. Most atheists are agnostic too, because agnosticism follows logic.
It's an absence of belief in a supernatural deity. Nothing particularly special.
Believers are so used to believing in stuff that it's hard for most to grab the simple concept of atheism. One may argue that beliefs are natural. Of course, but they're not to be taken too seriously. Since they lack empirical evidence, they have a high chance of being wrong. Because of his lack of belief in a deity, an atheist could even wish for a god to exist (and have tons of other unrelated beliefs), and remain an atheist. Atheism shouldn't even need a definition. It is the default mindset for any baby when they're born. Also, it's impossible not to be an atheist towards at least a majority of gods. Worshiping all the gods ever invented, all at once, would quickly lead anyone to despair.
But if we're going to argue about something, please try to debate this (without needing any kind of faith-based argument) :
Being unable to prove the non-existence of anything, is perfectly normal, and doesn't prove the existence of something. You can try to reason this way, but will automatically fail, because trying to prove a negative is ridiculous. Being unable to prove a belief wrong changes nothing to the fact that a belief is fallible.
