I particularly liked this one:
If you are failing this course, do not make sly little suggestions about what you might do to earn a passing grade. You are failing the course — why should I think your performance would be better in any other areas? Besides, I'm too old to care.Though, to be honest, I think this type of sly offer never actually happens. Or maybe it is just that I always taught the honors students at UWO, and never the general students.