It is important in any quality improvement process to define precisely what it is that you are trying to improve. Sloppy and imprecise definitions will make it hard for you to measure your process, much less improve it. But sometimes this effort to define things can go to far, as illustrated in this cute story on rec.humor.funny.
My favorite specification is “Outer-diameter of all pipes must exceed the inner-diameter. Otherwise, the hole will be on the outside of the pipe.”