I worked for one company that developed financial software for banks to approve loans. The company signed a contract with a big New York City bank to deliver loan approval software. However, the bank would request changes to the software as it was being developer; the company did not tell the bank that the changes would require X amount of additional money and time. As developers, it was frustrating to develop for a moving target and sometimes after one piece was finished, we were told that the bank wants it to work another way. There were death marches where we had to work on weekends.
The company even used the "Nine Pregnant Women Project Management" model from the Fred Brooks book, the Mythical Man Month, by hiring contractors to help with completing the project; but that caused delays because we had to get the contractors up to speed with the software and database. Besides, with the constant changes, there was no way to finish an endless project. The company lost the bank contract and its other customer and eventually disappeared.