the universe being billions of years old and not 5,000, the fact that everything has a rational explanation we know animals weren't just placed on earth and that they evolved from single cell organisms, the fact that there has been no evidence provided that a god exists. Especially when you talk about the god of the abrahamic religions of the hindu gods or the greek gods or the Pagan gods these gods do not exist as the people that made them up said they did things that we know they didn't do,
We know the sun isn't pulled by a chariot across the sky, we know the earth rotates and also rotates around the sun.
we know the rain god doesn't make it rain and that rain is evaporated water from oceans, land and rivers that condenses as it gets higher turning back into water.
we know the earth isn't 5,000 years old as we have carbon dating and radiation dating that can accurately measure the age of carbon and so on.