I was curious when I saw the title “Why do we laugh inappropriately?”. In my opinion, laugh is the most directly way for people to decribe their happiness, sometimes people may laugh inappropriately, but does it really has connections with science? To find the answer of this question, I read the paragraph and start to understand this situation. I really prefer the example the author gave at part “Infectious giggles”, she shown two different sounds of giggles to compare the most possible attitudes in them; one of them seems happy, another one seems like kind of sneering. I was confused about one situation, it was when a people near me is laughing, I also wanted to laugh with him/her, which was out of my control. Fortunately, this paragraph answered me that laughter especially giggles is actually infectious, thus, I know the truth behind the situation and I will never be anxious of this problem.