Funny video of high school student calling his teachers by their first names

When I was in high school, it always felt very uncomfortable speaking a teacher's first name aloud, almost like they couldn't really have a first name beyond Ms., Mr., or Mrs. (In fact, it was an odd transition to university when many of my professors preferred to be called by their first names.)
In the fun video below, Adam Lamberti walks through his high school greeting teachers by their first names. Some of them couldn't care less. Others are clearly discombobulated by the experience.