Everyday we use colloquialisms. Sometimes the elements of the phrase are obvious, sometimes we only assume they are obvious.
For example, I always thought mad as a hatter came from "Alice in Wonderland," but it actually had to do with the fact that hatters used Mercuric nitrate to make felt.
I learned this from the most delightful book, "What's in a Word" which I received from Book Sneeze,* Thomas Nelson Publishers.
With this book, you don't have to become an etymologist to learn the quirky details of word and phrase origins. You don't even need to be interested in word origins and history to be amused by this book. Each word or phrase has a quick paragraph summarizing the original language and if possible, a bit of history about the word. It was easy to read and easy to go back and find specific words when I wanted to share a specific detail.
It is a perfect book to keep with you and read whenever you need to kill a few minutes (or more.) Although I read it cover to cover, it is separated into chapters such as Fine Arts and Religion, Household, Growing Things, etc.
Even chapters which covered subjects that don't interest me had intriguing stories. I thoroughly enjoyed this book.
*I am not required to write a positive review for my free book.