"We are going to die, and that makes us the lucky ones. Most people are never going to die because they are never going to be born. The potential people who could have been here in my place but who will in fact never see the light of day outnumber the sand grains of Arabia. Certainly those unborn ghosts include greater poets than Keats, scientists greater than Newton. We know this because the set of possible people allowed by our DNA so massively exceeds the set of actual people. In the teeth of these stupefying odds it is you and I, in our ordinariness, that are here."
-Richard Dawkins

I don't generally debate people who have no credentials, credibility, and/or good evidence.
However debating those who claim god is real, and they know what he wants is a different story.
That is the only claim I can think of where lacking credentials, credibility, good evidence, or even a coherent argument won't hinder the speaker from being unquestioningly believed.
-TheNakedAtheist

I have very vague memories of when I began to realize god didn't exist, or that there was no evidence for his existence. I was 12 or 13 at the time, and initially found it very frightening idea, I think that feeling makes the religious believe there must be some powerful pseudo-religious faith at work that makes people "convert" to atheism.

What they don't realize is that being an atheist or agnostic isn't something you wake up one day and decide. You don't think "I'm going to become an atheist today". You don't stop believing because you're angry at god or because you think religion is destructive, though you may come to that conclusion in time.
It's more like learning that 5+5=10, whether you like the idea or not you can't do anything about it, I didn't make any conscious choice to become an atheist it just happened as a natural result of education, asking questions, and having a willingness to look honestly and objectively at the world around me.