The Lucifer Lamp is kind of horrifying, personally.
It's oen thing to go through life, thinking, "Yeah, magic thingies are out there. Neat, but not my thing."
It's quite another to get one of those, flick it on, and see, beyond a shadow of a doubt, that everywhere you go is chock full of invisible Things that are doing who knows what, watching you when you sleep.
Gah.
*heebie-jeebies*
(On the plus side, astral security firms must have made a killing in ward sales!)