I just realized the theme of this matches, and it was so subtle that I realized that this feels like a clash between generation, with two veterans and two youngsters. I like how it wasn't shown until now, because we were so mesmerized by their character that I even forgot until now. But Harada-sensei might be another favorite of mine after this episode (Another megane man). He has been receiving so many memorable scenes and character defining moments that it's hard to look past. I'll be waiting the next round in the next episode!