Weird stuff used to happen at my house. My wife (girlfriend at the time) absolutely agrees too. Our keys would move from one place to another, little stuff like that. But it would seem to increase if we were gone and came back, like if we went on vacation or something. We nicknamed it "Ghosty". And she read up about paranormal/poltergeist activities, and that they want to be acknowledged. So we would always say goodbye to "Ghosty" when we were going away or something. One night I was playing pinball by myself downstairs, and all of a sudden the hair on the back of my neck stood straight up, and i could FEEL something right behind me - I whipped around, of course nothing was there, but I shut all the games and lights off and went upstairs, I was that rattled.
I've been renting the house out about 11 years now - a pair of girls (well, in their early 40s - women) lived there almost 6 years, and about 3 years in, we were talking and I mentioned to them "the house is haunted, by the way".... They both said, Oh, I believe you", and said that the oven door would just pop open by itself, other things, but nothing scary or harmful, but they both said they felt something.
Just last year, I had to evict a couple people after only 5 months (first time ever). Three days into their stay (in December), they called me at 1030 at night, the furnace went out (have never had a problem with it). I went and dicked around with it and got it running again - no idea what it was. Then a day or 2 later, something else, and something else - smoke alarms going off, all kinda crap. I was over there 3 times in the first week. And my wife said "Ghosty doesn't want these people here". Well, after a few months neither did I, so we got rid of them, apologized to Ghosty, and have a nice young couple in there now. No more problems.