In FrameMaker's "Book" functionality, where you can stitch together a bunch of individual chapter files into a larger document, there's a very edge-case possibility of hitting a situation where there's no solution to the pagination (say that Chapter One has a forward reference to "(See page 57.xiv)" but added text puts the tagged info on page 57.xv, so the reference gets automatically changed to "(See page 57.xv)", but that text is shorter, so there's a slim chance that the reference has to change back to 57.xiv, but that makes the text longer again, which pushes the tagged info back to page 57.xv, ad infinitum).
Clearly, though it never happens in the real world, my code had to detect if a document seemed to be looping this way, and since I never expected anyone to see it, it just issued the one-word error message "Degenerate", with the intended meaning that "this document has hit a degenerate case".
Well, of course some customer found a bug that triggered the message, and called tech support, irate that our software had called him a degenerate.