Goi-sensei to Tarou  

五井先生と太郎

During school, there's just one student named Tarou who gets addressed with a formal title by their teacher, Goi-sensei. This bothers Tarou because they are the only person in class with this name and it seems unnecessary. Over winter break, Tarou visits Goi-sensei in the hospital and learns about the reason behind using an honorific for them.