I've been watching the TV show about Navy Seals Training and the instructors are some of the most sadistic instructors out there.
They do have a thankless job and they seem to enjoy their work in making the trainees life hell while trying to make them Navy SEALS, one hardest jobs in the military. So, there has to be a certain hell for these instructors, what kind of place, I don't know.
When I was in Air Force basic training, I remember on locker inspection. The drill instructor was so desperate to find something wrong with 1 trainee who had the perfect locker. So, the DI ripped the trainee a new ass because of a dirty razor. Except the razor was brand new and never been used and when the trainee pointed it out, the DI stammered about needing a new razor company.
So, I could never be a drill instructor, especially a Navy SEAL instructor- I could never be that mean or sadistic.