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
The traditional conception is that ghosts aren't really sentient creatures, but a phenomenon that souls can get stuck in instead of going to the afterlife. There's symbolism there - a ghost is an echo of a person, much like memories of them or the effects they had on the world. There's also a bit of Christian moralizing - a "good" person doesn't stick around because they are eager to join God in heaven, while a "bad" person clings to their earthly life and possessions even if they are only capably of doing so in a greatly diminished state.
The modern conception of a ghost where it's a fully realized person who can just kinda go through walls is an anthropomorphized and secular version of the ghosts that were invented by the Victorians.