A lot of that is the work philosophy. Ideally you'd work at exactly the speed that seems appropriate, on an appropriate schedule.

But so many of the jobs require you to work faster than you should and longer than you should even if you're tired. I even had a boss tell me once that my work was too good therefore I was working too slow. They really want you to just thrash it out like a maniac. Which is exhausting and dangerous. Really takes the fun out.

I've also had sane bosses who knew what's sane. And now I'm my own boss and I keep a very sane schedule.