The Library of Congress catalog puts cookbooks in the TX category (T = Technology, X = Home economics. I'm not making that up.). So I sat down with my cookbooks and the online catalog lookup, and sorted and organized. When I was done, I had a completely correctly ordered bookshelf. It was great! It was perfec.... well, actually, that's funny.
There was a section that had six books in this order:
Northern Italian | Greek | Indian | Italian | Italian | Italian
According to the Library of Congress, that's correct (regional comes before whole country). According to me, that's confusing. So we have something that is right, but it doesn't feel right.
You guessed it: I moved the Northern Italian book to be next to its Italian brethren.
It's a useful thing to remember when we're testing. There's what the spec says, but we also need to consider whether the spec itself matches with the way the software will actually be used. When in doubt, and whenever it's possible, usable trumps correct. Every time.