Our house was never pitch dark and I shared a bed with my younger brother, so I was never alone. I just don't remember being scared. I use to get a little creeped out when I was a teenager and my family would go out of town. Being alone was always a time for an active imagination.
There was the time I was home alone and our ancient family heirloom grandfather clock "walked" away from the wall. I never did like that clock. My dad left it to me and now it is in my living room.
I should also mention when I was a teen and had a room of my own, the scuttle hole to the area below the house was in my closet. That bugged me. No particular reason. It just did.
When I was a kid, my friends had houses that had those little cubby hole closets. I hated those damn things.
One night I was home alone and snooping into stuff I didn't have any business snooping in. I found an old silverware chest in my mother's closet. Inside, I found a large manila envelope and opened it. There was a photograph inside. It was a closeup photo of my cousin in his casket. He had died at the age of 11 in a 4th of July boating accident about 12 years before I was born.
I threw the damn thing across the room, ran out of my parent's bedroom and shut the door. I was never the same after that. I had accidentally stumbled across mortality that night. I didn't like it. I didn't like dead people either.
I went back in the room the next morning, in the safe light of day, and put everything back where it belonged.