Could it be because I believe in the other world?
There are three theories as to why my ghost stories are popular to read, if not buy.
A) - I am an excellent writer.
B) - I believe in the world of spirits, and so this enables me to write a better story.
C) - A combination of both A & B.
Most of the people I have talked to over the years would say "C" knowing about and believing in something that does help you write a better story.
For myself, I would say "B" as for being an excellent writer that is a matter for my readers to decide.
I prefer to think I used to write stories about spirituality rather than ghost stories. To me, the concept of a ghost story gives the reader the impression the story is scary, and most of mine are about souls trying to find their peace.