Equally Ratter we could ask, why you don't think there is a god, but that would be getting into deep theological discussions that I really can't be arsed with. It is not opffensive that you ask the Q, and most would agree that often we question our own beliefs, hence my 1st answer above. I think we (in the UK at least) should be grateful that we have the freedom to express our personal beliefs without fear of persecution.
Belief in God, a god or some gods is a personal thing really, and if you don't believe you don't believe, simple as that. I doubt any proof I could give would convince you otherwise. Simlarly if you gave me proof that he/she/it didn't exist, I would still believe in ... soimething.
My belief is not about superstition or blame, although most religions are based on this. It is just a mechanism for a means in those most painful and ectstatic times to call upon something that you may believe in for comfort or thanks, real or not.