I'm intrigued by "deja vu": the sense of thinking that something that I have just seen had been seen by me earlier, although that was not the case.
This happened yesterday (or did it?) when I was taking a fairly long and somewhat devious walk.
As I think of it now, soon after my start, while on a good path I was rapidly (some what furiously) passed by a young man on a bright red bicycle. An hour or so later, after walking through rough ground, and returning to a road, the (or 'a'?) man on a red bike passed me again! 
All very odd.