When I was a kid (7-12), the house my family lived in had this terribly negative vibe about it.
There was this really creepy basement, the door to which was between the living room and kitchen. The basement, we've established, was built underneath the kitchen.
My dad would sometimes stay up late, working on his racing newspaper on the computer. Some nights, I would wake up after having a nightmare, and I would hear dad typing on the keyboard. So I would get up, scuff my feet so as to not surprise him, and ask for his comfort.
One night, I woke up at like three in the morning, and I heard my dad typing on the keyboard, so I got out of bed, scuffed my feet, and quietly said, "Dad...?"
Upon turning the corner to the office, there was no one, nothing there.
Just as frightening as not expecting to see anything, and then something being there, I booked my ass back to my bedroom, got in the top bunk, covered up, and screamed, "Daaad!" He got up and came running in, looking visibly tired. He was definitely not just awake and somewhere else.
No explanation for that.
Some other time, my brother (four years younger) woke up in the middle of the night, and saw a short, tubby man standing in the doorway of our bedroom. He went back to sleep, woke up hours later, and saw a tall, lanky, skinny man standing in the doorway. Both of them were wearing 1940s gangster attire.
Every once in a while, I would hear something or see the shadow of something walking down the hallway.
I was given a baby duck in second grade, and right as it began the transition from "peep" to "quack," it had a heart attack in the tub during bath time. A month later, my friend and I were hanging out in the room the duck was stored in (side room/office). We were talking about the duck, and I said I wanted to stop talking about it because I felt weird. In the brief silence that followed, we both heard an unmistakable "peep/quack" sound. We ran out of the room and slammed the door behind us.
Sometimes I would be laying on the end of my parents' bed, across the hall from that same office, and feel something watching me through the open doorways.
My brother and I got Razor scooters for Christmas one year, and because we didn't have a "smooth" area to ride around, my parents moved the table out of the kitchen, and we would do laps in the small area available. Looking back, I remember that the kitchen had a strange dip in the floor, right in the center of the room. The floor clearly sunk a good inch from the edge of the kitchen to the middle.
After a while, we moved out of the house to one that was much brighter, with more windows, and a much better vibe about it.
We always wondered about the creepy stuff, but ignored it, blaming it on the general negative energy in the house. Three years after we moved out, however, our parents informed us that a young man had died, killed himself, inside the house, six months before we had moved in.
There was an attic entrance in my parents' closet they never went into. And there was the incredibly creepy basement, under the kitchen, where the center of the floor sank. We're not sure how or where he died. Or if he was the first person to die/kill himself in the house. But he was definitely there.
TL;DR -- lived in a house that was definitely haunted. Dude killed himself inside 6 months before we moved in. Sunken floor in kitchen over the über creepy basement. Phantom keyboard typing. Ghastly figures in 1940s clothing. Dead duck quaking. Shadows and footsteps in the hallway. Incredibly negative feelings.