The biggest mistake atheists make is the same mistake that most theists make. Hardly anyone has investigated what gods really are.
Really? Seems like we've been investigating for 150,000 years. Also, anytime we tried to investigate we were tried and found guilty of heresy and ex communicated from our communities. Theists said "Here is the story and you must believe this story or burn in hell or die". They presented those stories as facts. In other words, everything we know about god(s) so far has been a lie. The Greek Gods, him visiting Noah, Moses, Jesus or Adam or Mohammad or Joseph Smith. So what we have are all lies/stories/legends/fairy tales. Or we have people who believe in generic god because they know the stories are all lies too but they just can't believe there is no creator. That's all. That's all we have on god. NOTHING.
Science has investigated what god(s) really are. They are something we invented in our brains when we were very primitive frightened superstitious but also imaginative creatures. Humans have always wondered what happens after they die. What happens to the fish after you kill it or the worm you use to catch the fish?
Just because you can't imagine something doesn't mean it isn't true and just because you imagine something doesn't make it true.
Agnostic Atheism is the only rational position to have. No one knows but based on the evidence, probably not.
It seems like mostly atheists just dismiss the concept. They write gods off as 'not real', or 'invented'.
"They are something we invented in our brains when we were very primitive frightened superstitious but also imaginative creatures."
Well, I think it's debatable which came first, us or god, but I agree that gods are mental constructs. But here's the thing: so are we. Human consciousness - unless you go with some supernatural explanation - appears to be a special kind of software, housed as encoded information in a brain.
A god or something might have made our universe but so far no signs indicate that is true. At least not yet.
And until we know the answer is to keep looking. Don't be content that whatever we don't know must be god. That's what they did for 1000's of years. God of the gaps is what that's called.
Why there is no god