On a consulting project a few years ago, I was brought in to help a Fortune 500 energy company make sense of the value at risk model that one guy had built over 20 years in VBA. Most of it was pulling from excel spreadsheets brokers would send daily with prices. What. A. Nightmare.
It was hard to decide what I hated most about the project. The mind numbing stupidity of it. That fact that managers had allowed this single point of failure, and then let the guy leave. Or... that it was all a fictitious dance, pursued because spinning off their trading operations, would get them millions in tax subsidies.