Walked: 25.2 Km
How is it that there are some friends that, after not seeing them for years, it's as if you'd seen them yesterday? It seems as if this is a quality of long friendships, but on ocassion I've experienced it with people with whom I've had good chemistry (not necessarily romantic).
It was Goethe who proposed that human characters are like chemical elements: some are like oxygen or hydrogen, able to bond with almost anyone. Others are require more compatible profiles in order to form bonds (with anyone other than the 'universal' types).
In the meeting of human souls, sometimes chemical reactions arise. I think the experience of meeting a brief acquaintance for a second time and feeling like you're picking off where you left off is largely a result of the memory of the chemical reaction experienced when you first met.