The act of rubbing your own hand around your sweaty ball-sack, then shaking someone else's hand with the aforementioned hand smothered in bollock sweat.

Briefly, "the realization that each random passerby is living a life as vivid and complex as your own." Originally from the Dictionary of Obscure Sorrows, which has a lot more beautiful neologism definitions like this you might enjoy.

When your hands are wrinkled so much that they start to look like the surface of the scrotum