Why is it so uncomfortable to stand really close to a stranger? Sure, there are the potentially icky things. Sometimes an elevator car is so crowded that you can smell a fellow rider’s shampoo or chewing gum (or worse). But even when a stranger is perfectly groomed, it’s usually a bit revolting to be pressed against him in public. Why?
Evolution seems to have programmed this discomfort via a brain structure called the amygdalae, a pair of almond-shaped brain regions deep within each temporal lobe that control fear and the processing of emotion. It’s your amygdalae that keep you from getting so close to another person that he could easily reach out, gouge an eye, and then drag your woman off by her hair.
Read more at Times health