Incredibly good article here on the director Hal Ashby and his completely obsessive work style. It was beyond unhealthy but certainly served him well in the creation of Harold and Maude, Shampoo and Heat. He's also noted as one of the few editors to ever make the successful transition to director; which is likely due to his bonkers work ethic.

I'm not saying I admire it but I do find it fascinating to read about.