It's basically music intended to be listened to alone. Such as on a dark night with some heat lightning off in the distance.
My most eerie Pink Floyd experience was in a Iowa cornfield. I was walking one of those bike trails near Cedar Rapids that go through a bunch of corn fields in a straight line. I had Pink Floyd on my MP3 player and the tornado warning sirens around me starting going off. It took me a minute or two to realize that the sirens weren't part of the music. I took off my headphones and realized there were thick, purplish clouds coming up from behind me. I had no shelter to take as I was about three miles from where my car was parked. Fortunately the storm passed by me and I only got a little wet. No tornado.
But thanks for the idea. Next time I have a party at my house and I want it to end, I'll put Pink Floyd on.
The Doors also works well too.