It's well known that cats have an innate ability to find the one person in the room with a dander allergy or a feline aversion. I think their whiskers are specially designed antennae for the purpose. Sure as chocolate melts in the sun, if you are silently chanting "Don't jump on my lap... Don't jump on my lap... Don't jump on my lap." yours is the lap into which he will leap; yours will be the ankles around which little Puss will twine his lissome body; yours will be the sock on which he leaves his hairball gift.
In much the same way, my family attracts boundary-immune people. Our personal space is roughly the size of the Millennium Falcon and we do what we can to preserve it without holing up in a fortress on an island in an unnamed sea. I will sit on this couch... you can sit on that couch... and if there's anything I need to tell you, I will leave a note in your shoe. (Unless you're a squishable nephew, in which case you must be in arm's reach at all times, so I can squish you.)
We park at the far end of the parking lot, only to find on returning that four cars have parked so close we cannot open our doors.
We choose an isolated booth at a restaurant, and the next diner will take the booth next to us, while the rest of the tables remain empty.
We pick a removed, isolated, out-of-the-way road home, and a large pickup truck will keep his bumper in our rear view mirror the whole way.
Riding the train for six hours, the car we sit in will be filled with well-behaved, mannerly people who mind their own business, reading magazines (and turning the pages very quietly). Except for the person beside us, who for five and a half of those hours, talks loudly in her cell phone about the problems she's having with her husband.
Going to the lake at the tail end of the day, the beach is very nearly deserted. The horizon stretches as far as the eye can see, and the feeling of space is so vast that even we can let our guard down, assured of intact personal space. Until a chatty family of four comes to stand so close beside us I could have held hands with them. And there is no feeling more odd than being in the middle of a large empty space with a perfect stranger standing so close to you you can tell what he had for supper.
Boundaries, people! Boundaries!