We all believe that we have took birth to do a certain task assigned to us by God.God has already decided our fate and lyfe and we adhere to it. We were in some other form in our last lyfe and would be in a certain way depending on the way we do good or bad in this lyfe.This is the principle written in Bhagvad Gita. Belief in God is a sensitive topic and proving or disproving of it, reaching to a definite conclusion is very difficult.
But I am interested in giving my view points with respect to it and if people get offended by it, I apologize in prior for it.
1. personally I don't like to believe in God. It has a few reasons which might be wrong but let me put my points in a logic so that it makes some sense. As far as my experience is concerned, blind belief in God doesn't prove its point. The belief in humanity makes a bigger sense. If we are supposed to do any task which is blasphemous and it helps a lot of people in a very good way, then we should go for it, rather than backing from it due to our belief in God.
Humanity is greater religion than any other religion. Compassion should be the foremost priority rather than any other priority.
2. I have seen people who do all the malicious things in the world, that is, kill somebody, extort, kidnap and finally at the end of the day, pray to god to forgive their sins. God loses his significance there. If God should have exist, He/she should have been punished by God much early so that he/she shouldn't be commiting more malicious things and by not doing this ,God is allowing a lot of good people to be scapegoats.
3. If there has been one God, it would have been better to believe at. As there are so many Gods, hence so many religions, people killed each other in the name of religion and God , wanting to prove that their God is superior.People still kill each other and will kill each other in the name of God and religion.This is certainly bad. If there has been no belief of God, religions wouldn't have been there and hence ruthless killing of people hungry to prove the superiority of their religion wouldn't have been there.
4.Actually lots of great books teach a lot of good things to follow, but a lot of things in them have been misinterpreted and the people wage wars in the name of these sacred titles, to prove their ridiculous points.
5.If we are able to do things rationally,ensuring that people don't get harm by us, then it isn't mandate that, we should believe in God.