Why do people insist that God must Physically Manifest to them, before they believe Him?

People who insists the physical manifestation of God to believe in Him are number one idiots. It is we who requires His blessings for a happy life and not He . Whether you believe Him or not He is least bothered and He is bust preparing for your next meal. People think they are smart but He is the smartest and time will tell that in every body's life.