I, personally, am very skeptical about the existence of ghosts/hauntings, but I have a friend who investigates paranormal activity like your father and is very much convinced of its reality.
Definitely intriguing.
I think television hype on paranormal shows makes people overreact to noises and shadows that can be easily be explained. And after movies like Paranormal Activity come out ... suddenly everyone who has watched it thinks their home is haunted. The imagination under the influence of Hollywood can created a lot of "activity" in a home.
Still, I tend to be a believer of "where there is smoke, there must be a fire". I do think there is another realm beyond the physical. But I am not interested in inviting them in or going after them. "Live and let unlive" is how I feel about it.
And I've had a bit of the unexplained happen to me, though not in such a Hollywood style. I've heard my name called when there was no one around. I was in the kitchen one day (I live in a multi-level home) and I heard, what I thought was my three grandsons, running around upstairs in the master bedroom. I went to the stairs and was about to yell up at them to come down immediately .... when I noticed they (and the dog) were all sitting in the living room behind me playing video games. No one was upstairs. Go figure?
Our dog is a ghost. Really. One day my husband was home alone. He let the dog out to do his business. Then my husband went to the bathroom to do his own business. When he came out of the bathroom, the dog was back in the house. The door to the backyard is a very heavy glass sliding door. My husband had shut it. We still do not know how our dog got back in. Dog walks through walls??
There isn't anything extraordinary about our home. It isn't that old, built in the 70s. It's in a nice neighborhood. No weird history.
I do not feel threatened or afraid in my home. We just have had about a half dozen "Hmm. Weird." moments, but we blink and move on. Actually my brother in law is half Native American and follows much of the traditions. We've learned about cleansing and purifying with salt, sage, and sweetgrass. Since cleansing our home it has been pretty quiet.
I live in Northern Nevada and in the Reno / Carson City / Virginia City are there are a number of old buildings reported to be haunted. One building in Virginia City was officially declared haunted by one of those groups from one of those TV shows that ghostbust.