There are 8 billion people whose "things" I am not interested in discovering. Why would I be interested in a random person's things just because they happened to be physically proximate?
Because "things" are interconnected. There's not just one definition of Thing, whatever your thing might be. There's your perspective on Thing, and there's other peoples' perspective on Thing. So, whatever it is, Thing is not something that you can understand in solitude.
Understanding it means understanding both your perspective on it, and other peoples' perspective on it, at the same time. That's most peoples' reason for wanting to interact with random people. They see it as an opportunity to refine their understanding of Thing, whatever it might be.