After building some automated regression tests to verify parts of the company website were working, it was discovered that a test case was missing.
Instead of a constructive meeting about fixing the issue and adding a test, I was reamed and my manager was reamed that we "missed this case".
Nevermind that the automation caught several issues before release in nearly every other aspect of coverage.
Nevermind that the missing test case was a useless feature added after the automation was completed.
Nevermind that automation was meant to be the last stop in the gate, not the first...

I was so livid after that meeting I nearly resigned on the spot. My manager was so livid over being told to write me up he was ready to resign.