I once gave the "cross train so you don't have a bus number of one" speech to a bunch of managers. Got some push back from one middle manager who said the comp

I once gave the "cross train so you don't have a bus number of one" speech to a bunch of managers. Got some push back from one middle manager who said the complex driving their business line was understood by someone had been there by 20 years and was getting rebuilt in a year or two and there's no point in wasting anyone's time meanwhile. I saw them a few months later where I got a free lunch as an apology. The only man who understood the complex code died of a heart attack while trying to prepare the next release. No one had a clue where to start making the required changes. And you know what? That's not my only story of someone dying and no one being able to figure out the code that only they understood.