Personal space seems to be a completely human concept. For me, I only want someone in my bubble when invited. This, of course, makes living in a city of eight million people a little rough, but I make it work. If someone breaks my personal barrier on the subway or standing in line at the coffee shop, they’re probably met with a mean glare or a little jab of my elbow.
Then again, this usually just extends to other humans. Our fluffy, friendly fur buddies have no concept of personal space…but you know what? I’m actually 100% okay with it. These other pets and people? Maybe not so much.