system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do people want to laugh in a staring competition?
gpt
Our deep down animal side makes us feel a little nervous if someone stares at us wide eyed with a serious face. This is because before we were the humans we are today who can communicate with words, we used to be animals who had to talk using our bodies. Staring without flinching used to be a way of challenging someone's dominance and is sometimes used today when two people fight and/or argue. If two people who are friendly stare at each other nonstop, they will feel awkward and often laugh to break the tension felt from our evolutionary instincts to fight. 


Tl;Dr If two people stare at each other they both feel nervous, not because they actually want to fight but because of our evolutionary history and how we used our bodies/face to speak for us. We laugh to break that tension.