There are some things which are so far out there they have absolutely zero basis for belief. Ghosts are one of those. It's fun to think through as a sort of logic puzzle, though, as to how ghosts would actually interact with the real world. I'm stealing the following example from Dr Unne.
Say there's a ghost in front of you. Does that ghost have mass? Most people would say no (insubstantial and all), in which case the ghost would appear for only a tiny fraction of a second before the Earth, hurtling through space, left it far behind. We also couldn't see it because there'd be nothing for the light to reflect off of. If you say the ghost does have mass, just an incredibly small amount so that it could still pass through things, then any tiny gust of breeze would send it flying. Unlike some supernatural explanations, we have plenty of reasons to believe that ghosts
can't exist.
For every so-called event where there just has to be a ghost/spirit/whatever (which usually comes down to a strange light or sound), it just amazes me how so many people suddenly jump to supernatural ideas.
Occam's Razor - the simplest explanation is almost always correct. And in all of those cases the simplest explanation is that
something natural happened - whether it was light reflecting off of something you didn't see or an unnoticed cat moving around.
I've had plenty of incidents where I heard something I couldn't identify or a light was on I could've sworn I turned off or my keys were somewhere I didn't think I left them, etc etc etc. I shrugged them off as me forgetting what really happened or just not knowing. There's no reason to jump to "ghosts." There's a reason there's no legitimate scientific inquiry into the so-called "paranormal," when there are cameras and receivers and satellites pointing in tons of directions at all times (and for those that say ghosts can't be caught on camera, then we couldn't see them, either, since it's all just reflections of light).
Ghost tours and stories and stuff are fun, though. Classic entertainment. It is fun, but just because you may want to believe in something is no basis for actually believing. The TV shows are just that - entertainment.