'Should teachers always be kind and nice to students?'

[Body 1]
TS: Teachers  get lots of stress.
SS: Teachers being kind,  students neglect teacher and it can be difficult to control them.
AE: When the students are so noisy, students don't listen to teacher and eventually, teacher gets lots of stress.
CS: This clearly shows that teachers don't have to nice to students.
[Body 2]
TS: Students can learn more and correct their mistakes by receive scolding.
SS: Teacher can scold students and they can know new things and concentrate more.
AE: As teacher correct students' behavior or mistake, students can look back what they did and they will be afraid of teacher's scolding.
CS: This example clearly shows that teachers don't have to be kind.