I actually love this drama! It was extremely entertaining, emotional and had no boring parts. Ill start with the plot.
Many people dislike the unrealistic plot of this drama but I really like it, especially the way they executed it. A student being kicked out for school violence and returning to school years later for revenge only to find out one person who betrayed him became a teacher and the other a chairman of the same school.. I think the drama itself was very well done, It was funny, it was very emotional and full of angst in my opinion and really brought a lot of complex topics together. I loved the concept of students and the pressure they were under. A lot of dramas explore this topic but I love the way my strange hero did this. They romance scenes were cute and i loved how the relationship between the main couple originally formed. It was simple and realistic but also very well done. The sad scenes of the drama were very impactful and upsetting, the comedy was lighthearted and enoyable. Overall I love the story of the drama and the way it was executed. It was very consistent and entertaining, they new exactly what to do and where to do it.
the cast-
Yoo Seung Ho was great, he had a very nostalgic style of acting in my opinion. The highlight of his character was his smile and impactful performance.
Jo Bo Ah was new to me but she did really well. Even though Soo Jeong had many flaws, Bo Ah made her feel very real and sympathetic. Her performance was great and very believable.
Kwak Dongyeon was incredible! By far my favorite role by my favorite actor. I've noticed he's very good at playing tragic characters and he did amazing here. I have so much sympathy for Oh Se Ho. The little details he added to his performance, his sad and forced smile and the pain in his voice when he yelled was heartbreaking. He truly created that tense, overwhelming and sad atmosphere around him. I absolutely loved every scene he was in and enjoyed this role too much.
Special mentions for Kim Yeo Jin who is fantastic in playing villains and made me hate her character so much. The actor for Mr, Park was an amazing teacher and a very emotional yet funny actor, he's a true example of teachers being true heroes. I always have a lot of respect for teachers because I've had many good teachers in my life who all really scared about students.

The cast of this show was so amazing, they all brought too much emotion to their characters to the point I personally cared about every character. I think that even though the plot of this drama was quite interesting, untilmately it was the characters that truly brought the story to life and added so much emotion to this drama.The actor for Chaemin and the ivy class were also great and really created that tense forced atmosphere.
Every character was written very well and built up very well. The main 3 characters (Bo Su, Soo Jeong and Se Ho) were all build very well and I loved how the flashbacks slowly but consistently peeled off the layers of their friendship and really made us sympathise and understand each character. Each one of them had their moments of hurt and pain. Soo Jeong seemed very remorseless for what she did for a while but slowly, we began to understand her and why she felt and acted the way she did.

Same with Se Ho, he was developed very well and his character made a lot of sense. I could talk for hours about him. He was 2nd in the school out of 300 kids but his mom was never proud or satisfied of him despite how good his marks were. Then he saw Bok Su who got really terrible grades but was adored by his friends and family. Bok Su had literally everything Se Ho never had despite how hard he worked. He was a very awkward kid with an abusive mother so naturally he never had many friends or healthy relationships so he didnt realize that it was normal of him to feel jealous of Bok Su. I think he couldnt understand why he felt this way towards his friend and that was the beginning of his hatred. He thought Bok Su was a bad person for making him feel so miserable when in reality it was his mothers fault all along. I ended up feeling awful for him and admiring how he changed.
It was also cool to see how much Bok Su managed to inspire the students or wildflower class, he truly proved that good marks do not make a good future and that school was really a safe and fun space for many kids which is actually something I never really thought about. At first I agreed that students who arent good at school should find an alternative but Bok Su really had a point. School is important for other reasons, namely friendship, social experience and just fun.

I was a little bit sad with the ending, I understand why Bok Su didnt forgive Se Ho but I feel like he was kinda harsh even though Se Ho tried really hard to mae up for his mistakes. Se Ho's last scene seemed inda unfulfilling. It was great that he matured so much and forgave his mom but he was all alone in that empty looing place. It felt lie he was as alone as he was in all his other scenes. I wish they showed him as being a less lonely person because he changed so much. It felt like he still had no one on his side. But I loved seeing his face look so peaceful, he normally looks so hurt and angry but finally he found peace.

Other than that, I found the ending quite nostalgic but also very satisfying. It felt like a pretty much perfect end. I often feel unhappy with ending of Dramas especially when they show the end years later but this one was great! everyone grew up but it showed that nothing had really changed.
It was a nice feel good drama. It was funny, cute and involved a lot of serious topics. The plot may initially sound strange, but its executed amazingly and it really shines in its characters.

This drama deserves the quote "and they all lived happily ever after"

This drama also had good OST and music. Some music sounded like action music, I loved the sad violin music they had and it really made the mood.

There fore, I love this Kdrama! 9/10, definitely recommend!