This Manga has so many flaws that it's hard to count. It's ok in the beginning, but after a while and especially at the end it feels like the mangaka didn't know how to end it well and said "oh whatever". The characters make a 180° turn. It feels like chapter 1-3 were all lies. If one doesn't know how to write a story where hate converts to love, then one shouldn't.
What I extremely disliked was how corporal punishment in school was treated. Both main characters thought it was fine, the school director didn't want to do anything. Even the punished student didn't feel too bad about it (although he and his mother told how terrible it was, it was only communicated through speech and not shown in mimics or actions). While I'm totally ok with portraying difficult topics like that, in my opinion they should be a bit more realistic.