My sense of it is that these flash mobs reaffirm the core connection between all humans, the affinity among humankind. Every stress, loss and painful trauma we carry around with us is a betrayal or violation in some way of that fundamental bond with our own species. The reaffirmation of it brings on tears of relief and also of remindment of these things. The last one didn't make me tear up, but these always give me a big old grin, and a sense that a small slice of peace on earth has slipped through the bob wire.