People will also sometimes puff out their cheeks and exhale.
Your neck is home to many nerve endings that, when rubbed, will lower your heart rate and comfort you.
In fact, it can play a much more important role than even the words we speak.
Dr Albert Mehrabian is a psychologist that created a breakdown of effective human communication: 7 percent spoken words, 38 percent tone of voice, and 55 percent body language.
Of course, this only applies if the person could comfortably and naturally point their feet at their partner---if you're sitting next to each other on an airplane, this doesn't apply because it would be very difficult for them to point their feet at you.
But if you're standing facing one another, and you see their feet start pointing towards the door, you might want to graciously bring the conversation to a close.