Something occurred to me the other day. Assume for a moment that there are ghosts.
There is an afterlife, but it's the same place as regular life. Use your own ideas about how much of the population gets an afterlife and your own ideas about where you go. Just leave right here as an option. After all these millennia of existence as a species and there's gonna be a healthy population of ghosts here.
Now, I'm thinking that if I were to pick a place to haunt I'm gonna pick somewhere that would be interesting despite my inability to touch things. I can still read, but I can't even turn pages or turn on a TV on my own. But, in a movie theater I'd get to keep seeing movies. At a stadium I'd get to see sporting events. I hate sports, but beats going up and down stairs at 3 AM for fun.
So why don't ghosts haunt those places? They're always doing basements and attics and abandoned farm houses, and whatnot. Why?
We're accepting, for the moment, that the world is filled with ghosts. Obviously, we can't see these ghosts. This would mean that we're likely walking through them all the time. I'm thinking that kinda hurts. Why? Because it feeds my hypothesis. As much as a movie theater would rock you'd have a lot of people to dodge. It would make sense that ghosts would want to avoid crowded places. Places where someone isn't likely to walk through you if your attention is elsewhere.
Thus, they gather in unfinished basements, attics, and run down houses. They hang out in churches at night and graveyards and abandoned houses. If they have a property they like they're likely to want fight for it when people try to move in. Thus bleeding walls and whatnot.
Do a ghost a favor. Open up a book in the basement. Periodically go down and turn the page. I'm sure they'll appreciate it.