Why Do Some Spirits Remain Earthbound?
First off, some (a small majority) spirits don't know they are dead. So it is not a choice for them to stay. There are only a small percentage of the deceased souls that stay Earthbound and don't know they are dead. For whatever reason, they do not know they are dead. They either had a shocking death and need to get over that shock. Then need to find out they are dead. Now, a spirit guide will try to inform this soul of this. Angels come to help. It may take a while but usually this is a quick process for this reason to not cross over.
They may have unfinished business. If they were murdered they may feel the need to see it to the end. To see the person caught, etc.
Soul's may be pulled to stay because of their loved ones. They are hurting over the soul's death and won't let go. So the Soul may choose to stay till they get over the soul's death and move on.
Or they may feel the need to stay and protect a person(s). There was an example in Echo Bodine's Book, Relax, it's only a Ghost, where a man stayed (who used to be a cop) in a massage parlor to warn the girls working there of not so nice men and/or women who come in. Even after she tried to help him cross over, he said he wanted to stay to help them. And that when he felt they were safe or he's done all he could do, he would move on to the Other Side.
They are obsessed with another living soul on Earth and chose to stay with them. This can be a problem. Please see How to get rid of Ghosts.
A Ghost may feel that they are being controlled/forced to stay earthbound and not able to cross over because of another ghost. An example is, a woman may feel her controlling husband is holding her here and stays. He may have murdered her and killed himself and is still intimidating her, even in death. When in fact, this is not the case. They can move to the Other Side whenever they want. No one has control over you, especially in death. She is free to go whenever she wants, but just doesn't know it.
OH, here is a popular one with ghosts. A lot of ghosts will refuse to go on to the other side because they do not want to face another person who has passed on already. Like for example, if a person was molested by they father, or treated badly by a person, they will flat out refuse to move on to the other side. But all they need to do is ask their spirit guide when crossing over that they do NOT want to see that person. And they don't have to, for as long as they need.
Some Ghosts will stay because they do not believe in life after death. They will ignore their spirit guides and loved ones who come to help them cross over, thinking they are hallucinating. They need to know that there is life on the Other Side after they physical body dies. They will be happy and live forever. Tell them to look for the light and go with their guides to the Other Side.
And the opposite from above, some spirits stay earthbound because they *do* believe in the afterlife, and also believe in the lies told to them by certain churches…that there is a Hell and that if they committed such mundane “sins” they go to hell. So their fear encompasses them and prevents them in from crossing over, till they find out that they will cross over to “Heaven” and will be fine. There is no hell in my belief system. The only hell is the hell some of us create for ourselves here on Earth. So reassure the ghost that there is no hell, and they can go with their Guides and Angels to live happily.
There are many other reasons. But remember Ghosts do NOT discriminate when “haunting”. They will go anywhere, it doesn't matter. Although they usually stay where they are comfortable, they can be mobile if they so choose. Always protect yourself by surrounding yourself with White Light and asking your Spirit Guides and Angel to protect you and let only those of Love and Light come near.