I have been in the consulting racket for several years and I have a story.
I was given a task for something or another four years ago. The sponsor
and I went to some "hell hole" and installed the system only to find the
assumptions were wrong. The sponsor knew he had a problem but said lets
make it work. We both worked 72 hours with minimal sleep - all the sleep
we got was stretched out on the floor behind the computer. We made it work
and he was a hero.
Guess what - he has been extremely loyal ever since.