Medaka (2004)

Takako Meguro's dream has always been to get married and quit her job. But one day, she finds herself working as a teacher at a night school. At first, she is unmotivated and doesn't take her work seriously. But she soon finds out that work at night school is tougher than she thought. There's a high-school dropout, a businessman, a cabaret girl, and many others—every student is either strange or extraordinary in one way or another. Half of the students are older than Takako, and she discovers that one of the students was her classmate in elementary school.

Now that she sleeps during the day and works at night, Takako is unable to attend drinking parties to meet guys. She starts to think that's how life is, and she should go with the flow. But one night, an incident ignites Takako's passion for her job, which explodes into an angry scolding of her students.