All of us have ratified that choice. When Adam sinned, he caused the entire world to come under the effects of sin. We live in an imperfect world, everywhere infected by wrong attitudes, and wrong deeds. Evil is in the world. And none of us are exempt from it.
Bad things happen because bad people do bad things.
There is also a powerful evil force in the universe. He name is Satan. He is also a creation of God. He was created, like we were, with the freedom to choose. He chose to rebel against God.