My favorite in this category was an old Macintosh extension named, I think, "Minitaur". Everytime you restarted the machine, it shaved off a single pixel of scr

My favorite in this category was an old Macintosh extension named, I think, "Minitaur". Everytime you restarted the machine, it shaved off a single pixel of screen space, replacing it with black. So your screen got imperceptibly smaller over time until eventually you realized something was really not right.