What's the origin of the idiom go south? Why is it go south only? Why not go southwest or go east?
Are the direction-related idioms go south, go north, go east, and go west correlated?
Example, go south from http://idioms.thefreedictionary.com/go+south:
- to make an escape; to disappear.
- to fall; to go down.
- drop out of sight
I've read a few times go east young man or go west young man, but I am not sure that they formally exist or not.