I had a client off and on for 16 years who took on a project for a national corp much larger than I (or I) could chew, but insisted on creating utterly insane schedules for delivery. I would constantly advise them to bring in more people...even though it would be taking money out of my pocket. I wanted them to get a good product. In the end, the impossible schedules were just that...impossible. The job did get done, but in the end I lost the client, and since pretty much every advertising industry is incredibly incestuous, I lost another large client to inter-company chit-chat. Basically ruining about 17 years of freelancing experience...in the area.

Luckily I have new clients who can organize and schedule properly, but it's still a scary experience.