We had a government employee who was responsible for building our mess of a Java project (it was done by hand). It was error prone due to some self-referential build requirements, and the deployment of projects had to be done in a specific order. Generally a deploy took a couple tries.
While I was there I skunkworks-implemented Jenkins CI (nee Hudson at the time) to deflect constantly getting blamed for broken builds and down time when they occurred. The side effect of CI was that I had automated away this government employee's entire job and reason for being paid. One day that employee was out but we still needed to deploy, so in my naive excitement was like I've got it guys, watch this, pointed the deploy target at our live acceptance testing server, clicked the build button and ta-da, gov. employee wasn't needed and nothing was screwed up. Even better, it was completely deployed in a few minutes instead of several hours.
What do you think the result was?
The CI server VM got turned off.