School...?

Today is your first day at this school. You look at the rules and realize there are only three:
1: Don't swear at school. It's an expression of emotion. 2: Wear the masks provided at the security desk. This is very important. 3: Listen to your teachers. If you don't, you'll be here until the last class. And the last class is 15 minutes longer than the others. This is to teach you proper etiquette and manners.
After reading the rules, you look at the bottom of this sheet. It says: Happy studying, kids.
You were quite shocked by what you learned. Then, you went inside the school. You were met by the security guard who stopped you and asked for your facial measurements so they could give you a mask. You nodded and began taking your facial measurements: face width, face length, eye width and length, etc. When the guard finished, he gave you a mask that matched your facial measurements. It was a yellow mask with a smile and yoke, exactly the right size for your eyes. At first, you hesitated to put on the mask, but then you did. Then, you were allowed to go further. Looking through the mask, you noticed that everyone was wearing the same masks as you and somehow managed to hear each other. You were surprised that they wore such masks in this school. In every corridor, you heard either the song "Happy Face" or songs designed to make people laugh and drive away negativity. You thought: "Do the teachers also wear masks like this? "When the bell rang, you walked into your classroom and noticed that your homeroom teacher was also wearing the same mask, and explained that she was your leader, that you shouldn't break the rules written on the sheet, and then the topic of the lesson.
Teacher: In this lesson we will watch a movie. I ask you to smile, okay? I want to hear you laugh.
The teacher explained the movie would be funny, so you smiled beneath your mask. The movie started. Watch it, because at that moment, Hypnotizing Hands emerge from under your desks, and if you're distracted, they can drag you under your desk, and then you don't want to know what's under there...