I fear losing wildlife. Whole species going extinct. Rising tides. The middle-class almost vanishing completely. Hate crimes higher than ever. No health care for elderly Americans and insufficient funds for social-security and Medicaid. People will die. Increased terror attacks around the world. A lot of chaos and that sort of thing. The reason? Politics, I’d probably say.
On the other hand, I think there will be a lot of good things, exciting things, to look forward to, especially in the fields of science, astrophysics, technology, artificial intelligence, self-driving cars, medicine (despite being too expensive for people to pay for without health insurance).
I don’t think we’ll ever have flying cars for common use, but many people will have IoT connected homes (that trend is just starting to catch on) and fun virtual reality devices. It will be a different world, but futures are almost always different than they were predicted. It’s fun sometimes to look back and see what was predicted for today.