The study of personal space is called proxemics, a term coined by anthropologist Edward T. Hall. Studying what is one's comfort zone, he concluded that I need at least 1.2-2.1 m between me and an acquaintance, but good friends can come within 45-75 cm.
Here is the variable: I'm a hugger. In Hawaii, I fit right in. Everyone hugs everyone else all the time. In my birthplace, New England, where showing emotions is suspect behavior, I am a distinct nuisance. One of my sisters noticeably braces herself when we meet. She murmurs, "just one hug," as she endures my need to make that contact.
In China, if I forget where I am and hug someone on meeting them, they usually freeze and simply don't know how to react to such an aberration of acceptable behavior. We are both embarrassed. Some of my Chinese friends have come to accept my hugs but some have not.
A term called "spatial empathy" was first coined by foreigners in Hong Kong who had great difficulty adjusting to being in close bodily contact with others at the incredibly crowded streets, markets, shops and official buildings. It's pretty amusing to think of those Brits and Europeans trying to navigate the narrow alleyways of old Hong Kong without touching anyone - and having all and sundry staring at them and laughing.
In truth, we are all creatures of habit. What feels right to me feels wrong to you. Sometimes, though, the logic is hard to identify. I don't like to be pressed up against in a line or a crowd but on the other hand I can easily hug strangers. I don't think even proxemics can find an easy label for that!