So speaking of personal space, of which I happen to have in an abudance - why in the first place would the concept of disliking the close approach of a fellow animal be uncomfortable? The phenomenon of personal space was introduced in a zoo, and naturally been a subject that could grope anyone into fascination, even of late. Obviously, it has to do with territory, but based on something primal, it now probably has more to do with precaution and intimacy than habitat.
For a long time (like let's see, yes! From way back in the grand Chinese emperors' time) it has been known that important, or famous people can feel all the more important and/or famous if they have larger personal space. Being untouchable is status.
According to our treasured Wiki, our personal space is breached if a stranger is closer than 70cm in front of you, 60cm on your sides - and stunning 40 cm behind you. This space is often called "the bubble".
Your name is Brian. Hello Brian. Brian has been drinking. You with me? And he is on a bus, naked, in a strange swimming pool. How big is your personal space?