WhereZat Come From?

Last night I was reading an adventure story – a team of heroes were planning a big planet-saving mission. Toward the end of the prep session, one of them had an additional idea, prefacing it by saying In case things go south we should.… 

I get that going south means that shit’s getting nasty, things are going horribly awry but how’d this phrase come to be?

To deteriorate or decline, as in "The stock market is headed south again." This expression is generally thought to allude to compasses and two-dimensional maps where north is up and south is down. However, among some Native Americans, the term was a euphemism for dying, and possibly this sense led to the present usage. (source)

I employed my spectaular Googling talents but could NOT find which nation of Native Americans believe this. There are, by the by, 562 federally recognized, ethnically, culturally, and linguistically diverse nations so…em…sloppy, sloppy, ignorant job Free Dictionary!

And OK, this is not an allusion to or slam on the Southern US as I'd first thought. Got'cha.

Another odd turn of phrase poking my bean lately:
Getting a bigger bang for your buck

bang = excitement
buck = money

I get it BUT where’d it start?

Wikipedia tells me that it originated with Eisenhower’s Secretary of Defense who used it to sum up the New Look policy.

...The New Look, a 1950s national security policy… was called “more bang for the buck” and “bigger bang for the buck”. “More bang for the buck” was also used in the late 1960s by the U.S. military to refer to how it wanted to receive more combat power from the armaments it possessed. The United States, instead of supporting a large regular army, increasingly depended on nuclear weapons to hold the Soviet Union in check. (source)

Remember the good old days when Republicans wanted to keep the Russians at bay? Ya know, before they were all bought off by pretty young temptresses bearing guns, moolah and illusory Clinton dirt.

*sigh* Bigger bang has lost it’s nuclear association and is now used more generally.

Minds.com posits a couple other possible origins:

1. that it comes from the explosives and mining industry, where it referred to the amount of power per unit of explosives purchased.
2. …some people are convinced that the saying came out of prostitution, and referred to the tendency for men who solicit prostitutes to hire those who would work for longer, or be more exciting. The timeline..., with the first use of ‘Bang’ meaning “have sexual intercourse with” first being recorded 1937.

OK, so no Big Bangs and no Big Bang Theories...gotcha.

One last and just because I've been in a pastry craving mood lately:

Brownie Points
dictionary.com tells me: The term originated with the points earned for various achievements by the youngest group of the Girl Scouts, called Brownies. In the mid-1900s it was transferred to general use.
 
The Phrase Finder, a UK site, says the expression hails from:

- The system of merits and demerits that was introduced into the work practices of the Fall Brook Railroad in New York State by Superintendent G. R. Brown from 1886 onward. The system was well used and widely known on the US and Canadian railroads in the 19th century. (source)

OK...whichever. I think I need a cupcake or, ya know, a brownie right about now.