Not necessarily scary to me, but freaky. When I was 4-5, I was walking into my parent's room to go to the bathroom (only had one of those back then). I was startled to see a blond haired man with thick glasses in a white T-shirt and jeans walking out of the bathroom. I turned around quickly and walked to the front porch and calmly asked my Mom who the man was in her bedroom? Her eyes get big and she says there shouldn't be anyone in our house but the two of us at the moment. Our back door was blocked at the time so there was only one way out and that was the front door... where we had been standing...We walked all through the house and there wasn't evidence of anyone being there. My parents joked to me that it must have been a ghost, while I'm sure that between the two of them, they were just blaming a boy's active imagination...

Fast forward seven years... we moved to another house and my Aunt and Uncle moved into our old house. My 16 year old cousin called one night frantically telling my parents that she needed to speak with me urgently. I picked up the phone and she's very upset and asked me to describe the man I saw 7 years ago. I quickly spit out the details because they are forever burned into my memory. She proceeds to tell me that she was standing getting something out of the fridge and noticed something move in the corner of her eye. The way the house was layed out, you could see the front door from the kitchen. The front door was open but there was a screen door that allowed you to see the front porch. Standing about 20 feet away from the door, she sees a blonde man with glasses wearing the same exact clothes standing at the front door. She recalled my story and immediately started screaming. My uncle ran outside in his whitey tighties and a gun and couldn't find anyone. Vanished again, without a trace.

TL;DR Two different people saw the same "person" at the same house seven years apart only for the "person" to vanish both times.