When speaking with the ghosts of a given castle, it is good to remember that some subjects are likely to be thorny issues to them.  For instance, discussing religion with victims of the Holy Inquisition of 1026 YB (common in castles of the White Valley region of the East Realm) is not recommended unless you wish to risk the wrath of some very powerful deceased wizards and witches.  A little education about who you are dealing with will save both you and the spirits a lot of grief.