[postfacto]

> they were demanding something in a timeframe that I couldn't deliver it without ensuring that there wouldn't be any unintended side effects - and then blaming me for the side effects when they came up.

Far too few developers understand: just because the people writing the checks ask you to do it and you implemented it exact as they ordered you to doesn't mean the people writing the checks will take responsibility for the resulting bad situations that can lead to them not writing you checks anymore. If anything, you'll be used as a scapegoat to prevent them from not getting any more checks written.