It's taught to them from infancy. They are programmed to believe in that, and most people do not have the ability to think logically and independently, or have the intelligence level to break away from the conditioning that their parents and society have been doing to them from childhood.

I use to believe in the supernatural, now I don't. Only if there was evidence, then I might believe in the supernatural.

Because there's always been things happening that human beings don't have an explanation for. There's usually a need to fill that void. Enter a convincing story teller, and over time, different cultures have different stories of the origin of life, of how God pisses for rain, ghosts, ghouls, reincarnations.‍.

Some buy into the BS that blind faith is a virtue. Therefore, they are hoodwinked into religion, where the church empties their pockets. Others, like myself, demand facts and evidence before accepting a claim as true. For those who can't decide, please know that religion is a scam, faith is NOT a virtue, and we are better off following the truth where the facts and evidence lead.

Unexplainable instances. That's it. I do believe some of it comes from a lack of understanding of both natural occurrences and medical issues but once in a great while something happens that neither seems to be able to explain... even for those who are pretty highly educated.