To atheists. Why dont you believe in Christianity?

Obviously, I know everyone has their reasons. But I just want you guys to extract alittle more. You guys may believe it's a fairy tale? or a form of brainwashing? Well, yes, I am a Christian, not a very spiritual one, but i do believe. You may ask me, why? I say, because i choose to follow whatever makes me happy instead of being miserable sometimes. Hmmm, i'm not an Evangelist or a converter, just another curious civilian. so what do you guys think?