Disagree with this Pete, there's a time and a place.
However it is rare, and shouldn't be done by someone who's had proper training.
I've connected and drilled live bus bars before. With all the procedures in place I wouldn't have said it was dangerous, sure there was still a risk. This is reduced with correct tools, PPE and methodology.
After all, cable jointer's work live most days for the DNO.
As to the thread, I think my most dangerous experience was working on a remote silo, during a thunderstorm. Got down pretty sharpish once I felt the hair on my arms an neck stand up. Was a strange feeling.