In Japan, students also have to be respectful to teachers. They must talk to teachers very politely, but American students can talk to teachers in a more friendly way than Japanese students. In the U.S., students' and teachers' manners in the classrooms are also a culture shock for Japanese students. In the U.S., both teachers and students are very informal in the classrooms. In Japan, however, students have to be polite during classes, or whenever or wherever they talk to teachers.
Most Japanese teachers are very particular about manners.
One of the biggest culture shocks I remember was when I saw a student drinking Coke in a classroom for the first time. At that time, I glanced at the teacher because I thought he might be angry with the student. However, he did not seem to care. Furthermore, not only students but also teachers bring something to drink to classrooms such as Coke, orange juice, or coffee. They also sit on the desks, and that is a scene which we cannot see in the classrooms in Japan.