It's a space issue thing. Unless I know you very well and you have proven that I can feel comfortable around you, don't touch me. Don't get within 3 feet of me. Wait, make that 5 feet. I don't want someone I just met casually touching my arm, let alone getting all up in my girly business.
So you can imagine my thrill that right now, as I'm sitting at Starbucks, someone decided to sit at my table. Not the empty tables next to me, not the empty tables ALL OVER the coffee shop. He sat at mine. He didn't even get coffee, he just came in with a friend and sat here. The friend is at the table next to me. Neither of them are talking, they're just sitting there. At my table. Within my space bubble.
This really just happened. I thought it might be rude to take a picture and post it online, but so is sitting at my table. So we're even.