Ask HN: What are the real dangers of AI that everyone is warning about?

It seems fashionable these days to talk about the dangers that AI will bring in the future. Some people even warn that AI will destroy lives of people. How exactly will AI do this? What exactly are the potential dangers? I just don't see the scenarios how AI could concretely do harm that would warrant such dire warnings. Any insights? Any concrete cases that readers here can point to?