Some persons have a strange approach to ghosts.
I remember talking to one of my father's colleagues, who lived a few miles from Birmingham, about his haunting. He wasn't sure if "the ghost" was either a butler or a maid, but he felt sure he/she was during his/her lifetime a servant in his house (which was built during King Charles I's reign) and he would have loved to know his/her name.
Also an historical city or building seems to gain importance if it can boast a famous ghost: what if the Tower of London weren't haunted by Anne Boleyn? What if Rome couldn't boast its many historical ghosts?