Some believe that ghosts may exist in a type of limbo and frequent or haunt the places with which they were familiar or have fond memories. Places such as childhood homes or playgrounds, places where they worked or spent a lot of time. In the case of a sudden or tragic death, they may be confused not knowing that they are dead or what has happened to them so they are trying to find answers to help them understand.
Ghosts or spirits may also appear a short time after their deaths in order to comfort someone close to them who is grieving. In helping the living cope with the loss of their loved one, they may appear to let them know that they are ok and that everything will be alright.
One of the members of a ghost hunting group to which I belong described several events that happened to his sister-in-law after the death of her father. The family was having a get together at the sister-in-laws house shortly after the death of her father.
The sister-in-law had twelve place settings of a particular set of silverware that they were using for the get together. After the meal was finished and the dishes were being washed, it was noted that a fork was sitting on top of the garbage pail, and sure enough, it matched the place setting that were being used.