I found this a while back, but can’t seem to stop myself from watching it… and watching it… and watching it again.
I’ve even resorted to quoting it, in the context of mocking a tester (who is no longer here) who’s idea of negative testing did not appear to be based on reality. To demonstrate that her testing was inappropriate, my example was a hypothetical dialog between a patient and a doctor:
Patient: Doctor, when I head-butt the wall, my brain hurts!
Doctor: Well, don’t do that then, Mr. Gumby.
OK, so maybe you had to be there, but it was supposed to indicate that your test scenarios that are based on something that never can or will happen, should be removed.