Why going south seems easier than going north

Quite a few months ago, I wrote that "south" has taken on a lot more meanings that the simple directional one. I got one response that I was playing with words.  I was convinced about what I had written, and that conviction is reinforced after reading this piece; here is an excerpt:

subjects were supplanting map-based metaphors for the actual experience of travel. "A lifetime of exposure to the metaphoric link between cardinal direction and vertical position," they write, "may cause people to associate northbound travel with uphill travel." 

Yes, that was exactly my point as well--that "south" and "north" have become metaphors for a number of different aspects of life.