I suppose my worst nightmare was being chased by a crazed mob all over the city, only to have one of them snap out of it long enough to explain that they were all the world's psychics and that they were chasing me because they were being driven mad by their precognitive knowledge of my eventual fate, and asking me to move to another planet so I would be out of range of their abilities and they could return to sanity. Fortunately, no, this has not yet come to pass.
My worst nightmare? Being strapped to a chair and being forced to listen to Dolly Parton's greatest hits for days at a time. I'm still alive so this has not happened.
When lawyers and accountants control decisions regarding healthcare, rather than doctors and pharmacists. Oh wait a minute....
Being chased by a hoard of zombies, without a firearm to defend myself and without the physical fitness to run very far.