When something
terrible surprises you when it turns out to be
mediocre, thereby juxtaposing the aforementioned
terrible something making it appear brilliant.
Susan Boyle is a
fugly man-woman. Her singing voice, however, is very average. Because she is so damn ugly, this surprised everyone into thinking her singing voice was angelic. It isn't.
Steve: The Wizard of Oz was a great film...
James: No it isn't. It just appears that way because it was made in a
period when all other films were in black and
white.
Steve: Aah, the Susan Boyle Effect!