Nightmare on my street

I rarely remember my dreams.. but last night’s was quite visual, and very memorable. The scenery was abundant.. the feelings I had during the dream was palpable. But looking back on it, I don’t quite why the night vision had such a foreboding threat of doom associated with it, but it surely did.
The premise was quite simple, actually.
I was driving –I think with my wife but, as dreams go, I can’t remember for sure–and we were in a mountain setting. It was dry and arid, looking like a drought-plagued dust bowl. The interesting thing, though, is that I recalled being there before. And it was not a good place.. 
As the dream went on, the discussion came up: What would be scarier: 1) If we see a house in the middle of this no-man’s land, or 2) if we saw a single person walking alone in the distance across the barren landscape.. We concluded that either would be alarming and would cause unease within the mind.. 

But why?
I mean, yes dreams sometimes take on a life of their own..

Looking back on it now, neither instance–a house or a lone man–really is scary in itself. But for some reason, that dream I had last night was actually a nightmare.. And I cannot figure out why looking back on it now..