This reads like a allegory for Hell. How to love working 18 hours a day could almost be the title of a satire novel on the failings of modern office life. The fact that she lived it and looks back on it fondly doesn't, in my mind, reflect positively on her or her employer.
Why so judgmental?
Working hard at things increases your likelihood of success. Is that notion in question here at HN? True, there is a diminishing point of returns for everyone where working hard doesn't yield more returns or even produces overall negative returns... but how can you categorically decry her and her choice to push her own limits?
I worked crazy hours before I got married and have a lot of financial and experiential success to show for it. I did it then out of choice. I don't do it now out of choice. Was I doing something inherently wrong when I was younger and working so hard?