Coming from someone who briefly bought into atheism, the thing that snapped me out of it was the aimlessness of it; if there's nowhere for you to go after you die, good or bad, than what's the use in living?

Anything you do will have no impact since once you're dead, that's that. You may have people either loving or hating you on a varied level, but that's short-lived since if you were to believe in the atheist mentality, you won't live with that guilt long after your physical life ends; the only "purpose" you'd have in a godless world is that of material maximization, having the most stuff in a world that rapidly depreciates the value of whatever you attain.

Some fucking life that is.