/pedantic mode on
South Africa is just over 6000 miles away, not 12000 miles away btw, unless you went a different route
/pedantic mode off
I'm from South Africa, was born in Port Elizabeth and to be perfectly honest with you, I've never been greeted by anyone walking around in places. We generally didn't walk around in the street because that was kinda dangerous, but in shopping outlets people just got on with things. When I was at school we would have to tip our hats to adults, but that was when we were younger and very few adults greet adults that I've seen. You must obviously just live in either a really friendly place, or a place that's been taken over by extra-terrestrial life or something.
However, I'd hardly call people not greeting you in the street hostile, and thus the subject of this thread really isn't relevant to the post. I think it's quite normal to not greet everyone you see. Most people would think you're weird, and you'd never get anywhere saying hello to everyone everywhere you go. And despite people not greeting you here, it is sure as heck better than the hostility over in SA, although Britain is slowly catching up now.