Perfect, here's my reasoning for not believing, or what should be more correctly put as -spend time- believing.
I don't believe there's any religion out there that has gotten it "right", given this, it hasn't stopped them from condemning or killing in the name of their given religion. I think humanity as a species would have much more vast accomplishments without this preoccupation with God(s).
It's weird having so many people that want some intangible thing to judge them, yet very rarely do they act in accordance with the doctrine which they stand beside.
It's not a matter of not believing, as not needing to believe.
I'd rather ask you, why should I believe in God, and given that, why should I condemn the way anyone else lives for not acting in accordance with the doctrine that I happen to stand beside.