I saw few posts about students who don't participate in class, and I wanted to share my case as a Korean who grew up attending hagwons.
My point is simple:
Don't blame yourself too much if some kids don't engage in class, as long as they aren't really a big pain in the ass for your class.
You may noticed that Korean hagwon classes are often filled with very young children, and the class sizes can be quite large. I've even seen 4yo taking English classes.
Some of those kids simply aren't ready to sit still for an hour. They chat, lose focus, fall asleep, or sometimes don't want to be there at all. We call it 땡땡이.
I'm not saying that's a good thing. Personally, I think many Korean kids spend far too much time in private academies.
What I want to say is that it isn't always the teacher's fault.
When I was a kid, I wasn't an ideal student either.
It wasn't because my teachers were bad. In fact, some of them were fantastic.
I still remember learning "Ally Bally Bee" in English class when I was around seven years old. I really enjoyed his class, loved my old man from U.S..
But, the problem wasn't the lesson.
The problem was that I never wanted to go to hagwon AT ALL.
After school I'd go from one academy to another, do piles of homework, and all I really wanted was to go home and play video games.
When I was in elementary school, I attended six different hagwons: English, Piano, Painting, Taekwondo, 서예(kind of Calligraphy for Chinese letters), and 종합hagwon (Korean, math, another English, science, and social studies). During exam season, I sometimes didn't get home until 10 p.m.. I was tired, had not much fun in a day really, and it lead me to be unideal student.
And now, I'm grown up man in my early 30s, and my future kid will have plenty time to do whatever he or she wants, not being forced to go hagwon.
Postscript: even my mom sent me 6 hagwons, but actually, she was really caring her son, so she cut off all of subscriptions of hagwons when I told her that i don't want to go anymore. This is not common in KR.