My main approach to explaining atheism is not to deny God but, rather, to deny any knowledge about the supernatural: and I think we can all agree that God is as supernatural as it gets.
A common response to the above assertion goes something like, "What IS the supernatural, anyway?", or "That depends on what you mean by supernatural".
So let's clearly delineate the difference between the natural and supernatural realms.
The natural realm is the entire universe and everything in it; including Earth and life. The supernatural realm is, by definition, outside the natural realm -- so there's NO evidence for it, NO contact with it, and NO knowledge of it. Any claim to the contrary is an insult to intelligence. Period.
Please note that I'm not claiming God does not exist . . . I'm claiming nobody knows anything about him (including whether or not he exists). Nobody knows what he thinks or plans, likes or dislikes, does or doesn't do.
Some believers might retort that we don't need direct knowledge of God because we have divinely inspired scripture from God. Of course, that's recursive reasoning; circular logic. If scripture is one's source of faith because it's divinely inspired, then one must presume God exists to inspire it in the first place. Maybe with all that circular logic, believers are too dizzy to think straight.
To put it plainly: denial is part and parcel of the suspension of disbelief required to accept the physically impossible claims and stories of scripture. When we deny reality, it has a way of coming back to bite us on the butt. Turn on CNN world news (anytime) and, within 30 minutes, you'll see plenty of confirming evidence for the consequences of denial. In fact, it can be fairly asserted that the Abrahamic religions have been THE most persistently divisive influence in the history of mankind.
We often hear that the zealots who destroy and kill in God's name aren't really "true" Christians or Muslims. How can anybody know that? The same "moderate" believers who claim divinely inspired scripture as their source of faith are the same believers who conveniently overlook the fact that the "zealots" they denounce are the ones who actually follow the examples set in scripture. Unlike the moderates, zealots act with the certainty and conviction of their faith. You think you know what God wants and likes? Well, the zealots do to: and they have the guts to act on their beliefs.
The fact is, the Old Testament and the Qur'an reveal warrior Gods who kill with vengeance and without remorse. The depths of sadistic depravity contained in these 2 scripture are not reconcilable with a loving, wise and timeless, God. Why the hell are so many atrocious acts in "holy" scripture? One has to wonder what kind of God would divinely inspire scripture like that.
Having said all that, I must confess that most of my friends are religious. My wife is a devout Catholic. I don't care if you're a faithful believer as long as you're honest about it. If you claim faith because you want or need God, then I say "Amen". If you claim faith because you know which God is the real one and you know what he likes and dislikes, then I say get the hell away from me! Don't come to me, uninvited, pretending to know what you can't possibly know.
Those who profess their faith as a subjective, personal, choice and without basis in logic or evidence, are being honest. They're not in denial. They don't claim a rational explanation for supernatural claims and they don't presume to claim knowledge of God's mind. It's the ones who do claim rational explanations for supernatural claims and presume to know God's mind, who are the problem. They're not being honest. They are in denial. Cocksure certainty of the supernatural requires some major rationalizations.
Therein lies the crux of the problem. Denial leads to belief systems built upon dishonesty. Certainty is a facade masking a web of delusions -- claims of knowledge nobody can possibly possess. Whereas "honest" believers recognize the subjective, personal nature of their faith, "dishonest" believers do not. They are threatened by disbelief and respond angrily when their faith is challenged. If only all believers could admit that they believe for subjective, personal, reasons -- and not objective, rational, reasons -- then religion would finally become the personal preference that it really is. Fundamentalism would evaporate and zealotry would fade away. There would be nothing (religious) to fight about any more.
A world without religious strife. The only ones who wouldn't like that are the news organizations.