This thread has been going 10 years now!
About 10 years ago, I was asked by my near neighbour to feed their fish between Christmas and NY because they were away. This is a house I had been in quite a few times - the fish were in her DC's room, in the back bedroom upstairs.
So the first night I went over, couldn't find the light switch for the stairs, thought meh, I can make it! Walked up the stairs and along the long landing in the dark, towards the back bedroom, and honestly, I have never felt so spooked in my life. It was freezing cold, and pitch dark and I just felt there was something evil there watching me, from the front bedroom by the top of the stairs.
Anyway I switched on the bedroom light, fed fish, and then walked back. To this day, I don't know why I didn't try to find the hall light - but I didn't - priding myself on being a grown up non-woo sort of person, I just insisted to myself that there was nothing to be afraid of! Walked back down the landing, down stairs and out - forcing myself to resist the urge to run, and couldn't bear to even glance at that front bedroom doorway. My heart was thumping like crazy - I've never felt such an oppressive atmosphere ever. I felt that something would grab me.
The next day I sent DH - he claims not to have felt anything!
Funnily enough, the final day I braved it during daylight hours - and the atmosphere was completely different - the house was warm & friendly feeling. It's not like I'm afraid of the dark - I just can't understand why I was so spooked, it was like something evil was present. I've never felt anything like I did that night.