How many shows with investigators or psychics have any of us watched where at some point comes the inevitable "I feel a presence"? This statement always elicits a mental response from me of "Oh, please..." It's easy to feel like something is hovering in a dark corner or just out of sight in any place that is creepy to begin with. I have certainly experienced this unnerving sensation in such situations, but does that mean that there really is a paranormal presence there? I don't think so (and many people will certainly disagree with me). It's so subjective, and so hard to prove or verify.
Having said this, I will admit that there was one time that I experienced this feeling in a way that does make me give it more credence than I used to. I do real estate photography and have done hundreds of houses. In one house the realtor was downstairs with the seller while I was shooting the master suite. The suite had a long hallway into the actual bedroom area with double closets on one side and the master bath on the other. I was shooting an office area off the back of the bedroom with my back to the hallway into the room. I thought the agent had come up and was walking in, and I turned to see nothing. Mentally shrugging I aimed my camera again, and I definitely sensed her walk in and up behind my left shoulder. I actually said, "one more second - almost done" and after taking the photo, turned with my mouth open to say "okay, all set" to see no one. I went out to the landing and heard the agent and seller talking downstairs. Could have been a spirit, could have been my imagination. There's no way to ever really know. And that's my point (problem) with this type of "evidence". It's not true evidence at all.