Why do people believe in God?

Why do alot of people believe in God? I mean, As humans in the year 2011, I Would think that fantasy and superstition would be gone by now. I mean, it has been proven where we have come from. Science shows us how what we have evolved from *PROOF* but christians get offended if i call them crazy for believing in an invisible man who lives in the clouds and who answers prays from each person in the world all at the same time * around 14 billion people* They think that we evulutionist are nuts! We have proof, all christians have is a book that was writtin 2000 years ago, and the bible was written about 500 years after Jesus supposedly was here. You would think that if he was so special a book would have been written during or right after his time. Anyway, There are no monsters under your bed, there is no tooth ferry, there aren't any demons trying to take over your body and there is NO man floating on a cloud listing to `14 billion people all at once.