Can't they discover the world beyond? Weren't they humans; don't they have the mind to move on and focus on something else, since trauma and grief will run its course, sooner or later, and not just haunt the living?
If I were a ghost, I'd be tired of acting like one... even if I was murdered or otherwise died untimely
With the exception of Casper the Ghost, I don't think I've seen the alternative take on it
This presupposes ghosts do exist, though I believe ye skeptics would tell me no, which, alright, you win the argument
Damn, that's some psychoanalysis you got there... that is a compelling stance on why it is so
Also, checking on the monsters, it makes sense, I tell you that... though I wonder who Frankenstein, the creator, reps, in this case