Why do people allow religion into society?

What if a country was founded on the ideals of Walt Disney? Sounds crazy, doesn't it? Well that's religion, just one large fairy tale. Why, then, is there all the useless pain and suffering because someone has a different opinion? Not to mention the illusion that you're always right because you believe in a certain book but not another? Imagine how much more productive we would be as a society if we scraped away the religion and made decisions based on what's right and fair. Why is there religion in the first place? Is it because people are afraid of what happens after they die? Or because people believe something the crazier it sounds?