To teach brilliant students effectively, some teachers change their behavior to deal with "backbenchers" who often test their patience.
Our Physics teacher does the same, but in a different way; he keeps them quiet by insulting them in front of people they like, which ensures they never disturb his class again.
It felt like magic when our Math teacher became friendly because he wanted every student to pass the 10th grade, recognizing it as a crucial, future-deciding year.
However, we dislike our PT (Physical Training) teacher's behavior because he always takes the side of those who fight with juniors or are disrespectful to other teachers.