All the time...

Hey, it's your class time we're wasting. I get paid either way and the school board isn't gonna let you get out of the end of year tests because we didn't cover all the material.

In 5th grade, my teacher was tired of waiting for us to quit talking so she just sat on the floor and hid under her desk for like 10 minutes until we were all quiet.

In 9th grade my civics teacher was mad at us for talking so he put a black dot on the white board and made us stare at it in silence for like 10 mins...not even joking lol

I went into a staff room at a school and the teachers had printed this and pinned it on the wall lol