and seems often to be people suffering in some way, doesn't it?
y'know, the brain is a marvelous instrument. it's been keeping us alive for a long time. and it doesn't do this by always being a calm, rational, deep thinker. we haven't been out of the wilderness that long, but when we were there, we had to make a lot of snap decisions (more like reactions) based on very fuzzy data. i got to experience this often and at full volume when i was suffering more from anxiety and panic attacks. there will be some little movement in your peripheral vision and it makes you jump. you see things that aren't very clear and your brain, the marvelous thing it is, interpolates and extrapolates on the data to create something that does seem clear. and so, you often find yourself having to stop, steady yourself, analyze, realize it was just a shadow, and move on.
and maybe some other people aren't really suffering at all. maybe for them it's more of a religious experience. doesn't matter though. it's still the same "irrational" brain doing what it does best, filling in the blanks where we can't see.