Matt Yglesias wonders where the saying "sick as a dog" come from, seeing as how most modern dogs are not sick very much.
Myself, I've started saying "hold your dogs" sometimes instead of "hold your horses". Dogs, I know. They are very, very impatient. Horses? No idea. I suppose they must be impatient too, hence the saying, but who knows anything about that? Why should I continue to propagate a saying that is meaningless to me?