I am not usually a "chicken little", but AI, in my opinion, poses the largest threat to our safety we have ever seen.
Unless stringent safeguards are built into programs from the outset, we will not be able to control a technology that has no real understanding of human ethics or emotions.
If you doubt this is a threat, spend a few minutes listening to Geoffrey Hinton. Hinton is a British-Canadian cognitive psychiatrist and computer scientist, most noted for his work on artificial neural networks. He worked for Google Brain until recently, but quit when he realized the risks that the technology posed.