For me it's definetly the way my parents raised me, allowing me to freely choose what I believe. They allowed me to question their belief (Christians) and they themselves question their belief too. We're not really Christians at this point.
My parents don't believe in most the Christian religion, which obviously doesnt really make them Christian.
For me, I have my own set of ideas. Honestly, I think believing in a God is nothing more than the need to. Yes, being raised in a certain religion helps making you believe in Him, but when you have the chance to question, it has more to do if you feel the need to believe in God.
I am perfectly happy with the way the world is. I believe that you make your life. It kinda works like that whole media hype thing The Secret, which I found funny that I always believed in that even before the book was written, and now suddenly so many people are like "OH MY GOOOOD!" Yeah, kinda funny.
Life is simple. It's complex because of the choices you make. You can either decide to sit and wait and find comfort with Jesus or God, or you get that from yourself. Basically, in both ways, you get the comfort from yourself, but in a certain belief, that comfort in yourself is being portrayed in God or Jesus.
That's how I see it.
But anyways, my roots are from my parents but also from my own life experience and need.