Warning:
For the ones who want romantic scene a lot. Please don't watch this drama. It won't satisfy your demand. It's a subtle and pure romantic drama. Instead of love scene, they always use math metaphor for their love. If you want detective drama, this drama is also not for you. Sometimes the writer make a plot hole so the plot is not logic perfectly.
Here are some reasons if you want to watch this drama:
1. There are some different aspects you can see only in this drama. The way they use math to describe something is beautiful and the love of characters for math are so amazing. I don't like math but the characters make me curious about it.
2. The ending is perfect. Even though the writer can make them become a couple sooner like in ep 13-14, I think the wait is worth for ML that he will become more mature and have more time to pursue his career. Like what Ji Yoon Su said after becoming a real man, the answer would find him. In the end, Ji Yoon Su meet Baek Seung Yoo again in the place where they met the first time. In my opinion, it is more romantic than a kiss scene. There is nothing better than when you meet a person you love at the right time. In the past, They were exactly the right person for each other but the wrong timing destroyed everything. Now they can live happily together and never regret everything happened.
3. I love the way the writer build BSY character that he is a genius but also a human. He has a lot of mistakes but these mistakes make him stronger and more mature. If you don't know that Albert Einstein is also a imperfect person, he cheated a lot and made his wife hurt many times. If someone is a genius in a field, you can't conclude they are good at everything in their life. Sometimes emotion make them do something wrong. I hope all of you can think about it and stop criticizing two main characters.
4. The way Ji Yoon Su supports and helps Baek Seung Yoo. When there is no one cares about him, she is the person who is always there for him. She is always knows what is the best thing for him. That's why she rejected his love when he was a student and even when he became a adult. 21 years old Baek Seung Yoo was still childish and stubborn, he loves her but the way he showed his love made her get into trouble. Finally he can understand what Ji Yoon Su said and use his time to pursue the right thing for him. When you are in twenties the most important thing is improving and proving yourself, love can come after that. She rejected him many times in drama, it doesn't means she doesn't love him but she loves him so much that she can let him go to become a better person. The unconditional love between two main character is amazing. I hope you guys don't misunderstand their love.
5. The acting of every actors and actresses is awesome. From the supporting roles to main roles, they acts so well. Sometimes I thought everything is real. I immersed in drama so many times that I forgot about time. 10/10 for the actresses and actors.
Conclusion:
I love the drama so much. It's really brave to choose a different way to go instead of making a similar plot like other drama. I have experienced a new thing, so fun!!! I watch this drama because of Lim Soo Jung 's beauty and end up loving the drama. This drama will always be one of the most special dramas I have ever seen.