Too Long; Didn't Read
I guess that most of us have some horror stories to share about running our applications in production. Things that did not work as expected. Things that quickly got out of hand. Or even things that stopped working for no apparent reason. A great book with a handful of such horror stories is <a href="https://www.amazon.com/Release-Production-Ready-Software-Pragmatic-Programmers/dp/0978739213" target="_blank">Release It!: Design and Deploy Production-Ready Software (Pragmatic Programmers) </a>by <em>Michael T. Nygard</em>.