LOL this isn't some ghostly spooky stuff, but don't you hate it when you notice someone walk past you, and then later, then walk past you again in the
same direction? Supposedly if you see them again, they'd come back from the opposite direction, but sometimes you might not notice or they somehow go back to the start in another way, but I find it really weird and amusing sometimes.
Oh and this reminds me:
Threaded Mode