Where did they come from?
Examples>
“A cotton-pickin’ minute”
“Mind your P’s and Qs”
“Over the hill”
Molly Whoa! One at a time.
Or, are you asking “how” phrases such as these originate? As a general discussion.
Or, do you simply want to know the history of each individual phrase?
For example, cotton picking is a back-breaking job done by poor(usually black) Southerners. At least in the 1920’s and earlier, when the phrase was used to mean a “contemptible” person. Lighter(Am. Her. Dict. Slang) cites it from 1919 where it was listed as a negative thing to call someone along with “corn-crackers, stump jumpers, ridge-runners, bog-leapers.”
The first appearance of "cotton-pickin; " to mean “damned”
or “confounded” appears in 1952 Looney Tunes.
Oh, I can do one. Supposedly, “Mind your P’s and Q’s” comes from English Pubs. Tavernkeepers would say to loud customer Mind your P’s and Q’s or Mind your pints and quarts. So basically, if you keep up this behavior you’ll be kicked out and lose your access to the alcohol. Sorry I don’t have a cite.
Lost in Reality, I know that one isn’t true, but apparently Snopes has taken it down, or at least off their bloody search :mad:
Here’s where you can find two of those phrases: www.wordorigins.org. “Over the Hill” is not on there, though.
An AOL member’s Web site about word origins says it’s “obvious but interesting” (ie it means what you think it does) and that can be found here.
It’d be interesting to know how this phrase got started, though.
I’m surprised that the earliest known reference to the the saying cotton-pickin’ is from 1952. Looney Tunes character Foghorn Leghorn was modeled on the character Senator Claghorn (himself a parody of blowhard Southern U.S. senators), from the Fred Allen radio show of the 1930s and 1940s.
I could swear that Senator Claghorn, played by Kenny Delmar, used cotton-pickin’.
I always thought “cotton-pickin” was just a sly stand-in for “mother-fuckin.” Like a substitute a more proper person would use or something you would use around the kids. Same number of syllables and usually used in the same context.
Cause if you said, “wait a cotton-picking minute,” (how I’ve usually heard it said, from Black folks in Los Angeles with roots in the South) you’d be trying to emphasize the shortness of the minute you need to wait. Like, “can you wait just one minute?” A cotton-picking minute would be a long, hard one and the phrase doesn’t work.
But try “wait a motherfuckin minute.” Doesn’t that seem closer to the intent of the phrase?
Because we know how long it takes to fuck someone’s own mother? 
My WAG is that phrases like “cotton pickin’ minute” were invented for cartoons/televison so that the people could sound like their cursing without really cursing.
How about the phrase for doing one’s chores "doin my rat killin’ "? I use that all the time, and never really thought about it.