Reincarnation
I recently watched a series that touched on reincarnation. Part of the story had characters who came back but had no memories of their past lives. I wondered if all of us are just "recycled" every so often through the centuries. I think that would be easier than creating new faces.
The series also had ghosts, grim reaper's and a goblin. Being a Kdrama, nothing very bad happened and all the actors had interesting stories. They befriended each other as the story progressed and helped each other. The goblin had lived for almost 1000 years since he was cursed to roam the earth waiting to meet his bride.
Whether you are religious or not, these stories have been around for generations. I've wondered if our dreams hold memories of our past. Are there people who live today with some recollection? In a world full of distractions now, I find it harder to grow our minds and learn about our pasts. Society seems to not care about the past and focused on the now unfortunately.