The most stressful day for me was seeing the instant a company wide application that was already about fifteen years old and facing Y2K come to life after being killed by the milllennium turnover . The software was old and the application was huge - meant to keep the company's plant, property and equipment books containing records for several billions of dollars worth of stuff in pristine shape for the regulators (FERC). The project required review and corrections to what seemed an infinite amount of program code and when I made it back to work early on that first day in January 2000, I took a deep breath and turned the computers on. No one knew for sure that all the changes would work, having such a short time to find, fix and test them all for there were so very many. When the system did start up, it was like the thing taking it's first breath in the new century. To my surprise and relief, it started up...it lived! - and went on to live another ten years or so - Quite a very long time for such a giant complicated set of computer code to survive and continue being useful and productive.