From 1990 to 1993, I shared an older house with a couple of friends. During this time, because of various work schedules, I often found myself in the house alone. This led to several unusual occurrences that left my friends thinking I might be a bit crazy.
My first experience in this house was a bit on the creepy side. I was home alone with our German Shepherd, Max. I decided to go to the attic to look for something that I had packed away, and Max followed me upstairs. When I opened the door to the attic stairs, he suddenly put his tail down, his hackles went up, and he started to growl. I thought this odd, but I calmed him, then went up to the attic. I was up there for about 2 minutes, when suddenly the light bulb went out. I fumbled my way to the stairs, still not thinking too much about it other than being annoyed, went downstairs and got a new light bulb and a flashlight and went back up to change the bulb. Max was at the bottom of the stairs, and he started whining, blocking me from the stairs. I chased him off, went to the attic and changed the bulb, then went back to what I was doing. The next thing I know the new bulb blows out. I figured at least I have a flashlight to find the stairs this time, but no sooner do I turn it on and the bulb goes out in it, too! After that I got the heebie jeebies, and got out of the attic for the night.
My next run in with the unusual came a short time later. I was sitting in the living room tossing a ball for Max. I used to toss it over the stair landing, where it would bounce and roll into the kitchen, and he would bound over the stairs to get it. He chased the ball about a half dozen times, then suddenly stopped at the foot of the stairs. He stared up the stairs, his tail went down, hackles went up and he started snarling. I had never seen him act this way before. I got up, went to the bottom of the stairs and looked up, but saw nothing. I turned the light on, and Max suddenly relaxed and had a puzzled look on his face. I went up the stairs to investigate, but he would not leave the bottom step or chase the ball for the rest of the night. Needless to say, I didn't find anything upstairs.
My last occurrence before I moved out was rather humorous. I had a routine of coming home from work, go to the fridge, get a beer and open it, walk back to the front door, set the beer on the newel post at the bottom of the stairs and go across the street to get the mail. One day I came back, and the beer wasn't there. I looked all over the house, counted the cans in the fridge, and couldn't come up with any idea what had happened but decided it must be me imagining that I had left one out. The next day the same thing happened. At this point I was convinced that I wasn't crazy, my beers were disappearing somehow. The next day I deliberately set the beer on the newel post, walked out the door, turned and looked through the window on the door. It was there. I walked across the front lawn, turned and ran back to the window. Beer still there. Walked across the lawn, crossed the street, got the mail, came back and the beer was gone! Since nobody was in the house (I had searched earlier) I came to the conclusion that there had to be some mischievous spirit, troll, gnome or something in the place, so I yelled out, "Leave my beer alone. Go get your own!" Surprisingly, I never had another problem afterwards.