I'm walking around getting mad at my pain (normal for me) and I make the comment to myself: "son of a biscuit eater"!
I got to wondering where on earth did that phrase come from?!!

So I looked it up: "son of a biscuit eater"
means: It was a derogatory term used [by pirates] to describe a bastard son of a sailor.

Now how does that apply to how I'm feeling at the moment? It doesn't LOL

So then I got to thinking about other phrases we use and where they come from.

Sleep Tight:
the phrase dates from the days when mattresses were supported by ropes which needed to be pulled tight to provide a well-sprung bed.

Here is a fun site with tons of idioms, their deffinitions and the fun part: Where they originate from.
http://www.phrases.org.uk/meanings/american-phrases-and-sayings.html

Some were very intresting, like 'speak of the devil'
And "son of a gun"
And 'Basket case"

But I did not find my old favorite:
Dog gone it till the devil wouldn't have it!!!:)

Here is a fun example: Gee-whiz:
Meaning

An interjection or exclamation of surprise.

Origin

This little term derived in the USA as a euphemistic shorthand for Jesus; in other words it is a minced oath.

The first record of it appearing in print is from Cody and Arlington's Life on the Border, 1876:

"Gee-wees!...I'll bet one hundred dollars on that hand!"

The currently accepted spelling was used soon afterwards; for example, this piece of doggerel from the Pennsylvania newspaper The Warren Ledger, 1883:

When younger days have flown
And we are older grown,
We sit and muse -
We've got the blues.

Morning and night we fret,
And, cold or dry or wet.
In petulance pout -
We've got the gout.

We have accomplished naught,
Our fight was poorly fought -
Gee whiz,
The rheumatiz.