I worry about ethically immature people destroying the world; people doing things because they can, not because it's right.
I worry about smart coders writing AI unchecked. Or a biologist not being careful accidentally releasing a genetically enhanced disease that is in the lab "only for research" and causing an unstoppable pandemic.
I wouldn't be surprised if the apocalypse comes because of some smart person doing "what they think is right", either; not even an accident. Restraints on doing things never go over well, especially with smart people who don't believe safety precautions or rules apply to them.