In the everyday world we live in, there are lots of things going on that we don't notice. Like the fact that there is another world dwelling within ours.
The few that do know about this other world spent a long time trying to get there, but their attempts were futile. The only known way to access this world is with your astral body or spirit.
This other world, the Spirit World, coincides with the real world. Our world. So when things start falling off of the shelf, or there's random objects floating, this is the reason why.
Many things live within the Spirit World, or Astral Realm/Plane, including, as some would say, "demonic" creatures. You never want to anger a spirit. They can ruin your life as you know it. If by the off chance, you do anger a spirit, there is nothing you can do, unless, you learned to manipulate the energy around you.