Feeling the need to cry when talking about ghosts, what's this about?

I read this thing in a book about ghost study that when people tell one another experiences they may have had, or discussing the experiences of another or just hearing it…in all, it seems to revolve around talking about paranormal activity…when people get into it, they feel the need to start crying. What’s up with that?
Why would talking about this make you cry? Is this even true or are the authors nuts?