Unlike several who have already posted here, I have not had the sort of ghastly experiences people have written about; most of the jobs I have held have been interesting, and challenging, jobs which I mostly enjoyed, and a few of which I loved.
However, while there is no one job in itself which I can say I loathed, there are bosses who made particular work environments an absolute nightmare.
I have had two spectacularly dreadful bosses, - one a male university professor, and one a female head of department when I worked for the public service - the proverbial bosses from the abode of the rebel angels, and they, in turn, made the world which they presided over a living hell.