To believe in ghosts goes against my whole belief system, but once you've experienced it, it's hard to deny it. Maybe it's the way the 5th dimension interacts with our 4.
So, there have been a few incidents, but the one that comes to mind most when this topic comes up is the time I was helping my girlfriend move out of her family home to move in with me. We were there for a couple of hours, and the whole time I felt just a little something I couldn't put my finger on. I was just a little uncomfortable. Suddenly that feeling got a bit more clear, and looked at my girlfriend and said, "There's something here."
"What do you mean?", she asked.
Feeling a little silly, I said, "There's a...presence."
She turned very pale, and started telling me stories about green spots that just show up on the walls, the living room floor shaking violently for 10 or 15 seconds (Her father was a contractor, and he couldn't figure out anything that could have caused that, though he tried.), sitting in the living room and feeling her mother's arms around her, then realizing her mother wasn't there, etc. One time, she was in the basement and heard her mother walk into her bedroom, so she went upstairs to talk to her, but instead of her mother, there was a spot on the edge of the bed where it appeared someone was sitting, and suddenly stood up. There were a few more stories, but I don't remember them all.
Anyway, the feeling I was getting started off as just an innocent presence, nothing to worry about, and a couple of hours later we were sitting at the kitchen table, and it started to feel malicious, to the point that I felt like if we didn't leave immediately, thing could get bad. I said, "We need to leave...now."
As soon as those words left my lips, the garage door raised up about halfway and shut again...We scooted on out, and I never went back.