When I was in my early 20’s, I was in my room. I know for a fact I was not remotely sleepy (as it was only 8:00 or so), just sitting down and reading. Suddenly I hear a soft but clear voice go, “hello”. I turn, thinking I left my TV on or something, and find myself looking at a young girl, probably 8 or 9, with somewhat short black hair. I stared for like two seconds before racing to my right and then out the door so I wouldn’t have to run right by her, but I looked before slamming the door and she was still there though she was turning around to face me again. When I calmed down, I opened my door and she was gone.
I didn’t mention this to my parents. My dad will never believe in that stuff (or so he says, he did go with my mom on a tour to a certain haunted location, and my mom said he was clearly uneasy being in certain rooms), and my mom would potentially freak out. So I never mentioned it to them, and I only told my friends who don’t speak with my parents (as they live 30 minutes away and I always drive to meet them to hang out as it’s more reasonable than having all of them drive down to meet me).
Then two or so months later, I hear my mom scream for me from the large bathroom that connects to their bedroom. I rush in and she says she saw a girl run past behind her while she was at the sink, seeing the girl in the long mirror that goes across the two sinks. I ask her what the girl looked like, and my mom proceeds to give a description that sounded exactly like what I had seen.
I didn’t tell her what I had seen to avoid freaking her out, but did tell her most ghosts if they exist seem to usually not harass or threaten the people in the home and the girl hadn’t done anything malicious yet so we should try to accept it as a natural part of the house. While none of us saw her again, my mom would occasionally hear footsteps upstairs when she was the only one home, and one time she found two couch pillows in the kitchen which was like 15-20 feet from where the couch was and my mom knows she didn’t move them into the kitchen of all places herself. But beyond that, nothing.
And to clarify further, we have no idea who this girl could possibly have been. There were only one group of prior homeowners before my parents, and they did not have a daughter nor did anyone pass away in the house while they lived there. My sister, who was away at college at this time, did not resemble the girl plus my sister had and kept long brown hair well before and after she was 8 or 9 (the presumed age of the ghost girl). No one else my mom and I both know resemble or once resembled this girl.
So yeah, I feel very confident I, and my mom, saw a ghost.