Well, this certainly has got me thinking. I think being in a graveyard just serves to focus thoughts - I don't think very many people believe people's spirits hang around in them. You can do the same in another place a person spent a lot of time, or with an object someone loved. I don't have conversations with my mother, although I belive I did after she died in an unnecessary effort to keep part of her from slipping away. They were more along the lines of "what would mom say if she were here." They were chats with my memories of her. I think the reason I don't do this now is because her way of thinking and our shared memories are so much a part of me, I can't separate them from who I am.