Good points about the story/ plot/ drama
1-Very light , easy going, full of crazy fun drama, without villains, controlling parents etc
2-Throw light on a very unusual but deadly diseas
3-Shows the competitiveness and drama from behind the camera in the broadcasting industry, also in a very entertaining & engaging, non boring way
4-Deals with mature Issues related to mostly mature people like health, work problems, two timing ,asexuality etc.
5- A drama that is funny but if it were not a rom- com, it could have been easily a very intense Melo drama so writer did a good job by keeping an otherwise heavy story immensely funny
6- All the characters except for 2nd male lead was very realistic, the 2nd male lead was too perfect to be true.
7- One of the most hottest, sensual, sensational kisses from JJS , Gong Hyo Jin is one lucky woman.
8- The best of the best chemistry between main leads,and among all the characters.
9- Absolutely amazing OSTs, step step, would you to come to me, bye autumn are to name a few that leaves in my heart rent free.
10- Amazing bgm. Also very befitting according to the scene requirements.

Negative points about story/ plot:
1- Uninteresting side stories
2- Not everyone's cup of tea, very controversial for some .
3- One of the most annoying, unbearable lead female role
4- The biggest flaws
* The story and role of 2nd lead is very unnecessarily prolonged that makes at least half of the audience to root for him not for the main lead.
* The writer failed to bring out clearly, the reasons why male lead was a tusendear. she was unable to make a good no of the viewers like the male lead. She should not have made 2nd lead seemingly so perfect that many of the viewers could not connect to 1st male lead.

This drama is not everyone's cup of tea , like I said before especially for them who have over active brains, analyse dramas so critically, do not enjoy the drama for its face value, and don't take a drama as just a drama. And mainly for these reasons many dislike the main lead ,

But there are very few who dislikes female lead and I am one of them. The female lead almost through out the drama acts as a cringy ,puny woman who have no self respect, dignity, has no idea of someone's personal space,has no idea to let go and move on, wish-washy, indecisive on top of that is immature, naive. For me she only redeemed in the last 4-5 episodes and forother 20 episodes a little bit here and there. Even then she has the sympathies of all the viewers because she gets the benefit of being a woman and the portion of woman in the total no of viewers is always in majority.

On the other hand I absolutely loved the male lead who is a loveable jerk, little tusendear, a lot of arrogant ,have inner insecurities,think highly of himself but he cares in his own ways for his loved ones, actually do care for female lead when poses that he doesn't not care for her for various reasons for, he is charming, adorable, sincere, straight forward, all out honesty,sets the same bars for himself that he sets for others, and I was rooting for him because I understand why he acted the way he did. A major credit for it goes to Jo Jung Suk for his phenomenal, extraordinary acting. It was a fun ride to watch Hwashin's character growth.

A lot of viewers got the 2nd lead syndrome but I barely noticed him in my first watch, because for me personally he was very boring and bland. Again he is not a flawless character , he becomes clingy, not ready to move on from the female lead, was so rich but very weak in handling his personal matters, badmouthed his friend all the time in front of female lead to woe her back. But again just because he was good to the female lead and super duper rich so he was a perfect guy who gave some viewers 2nd lead syndrome.

I enjoyed every bit of the main story related to three main characters,it never got draggy, even though I had concerns with female lead but I was overcome with those concerns because female lead character is very realistic and such people like her exist. So the drama never got bored for me, I binged watched it in 3 days, I have rewatched it multiple times, I have saved it and come back to it time and again. I love it for it's crazy light theme, for its realistic characters, it's intense love triangles, it's flow, and for every good point that I mentioned above in the beginning of the review.
I hate it for making less efforts to make some people understand the main lead character and invest in him.

But I would say that this is one and only drama where it makes us to raise questions so very often on the behaviour of different characters but this never fails to stop us from watching it, from enjoying it, from craving for the next episodes.

Acting of every one was top notch except the 2nd male lead,he was good but not as good as others, but the one actor who totally shone , stole the show had to be Jo Jung Seok. I have fallen head over heels for him. He has made a seemingly unpleasant character , a totally loveable character, he made me believe in all of his happiness, insecurities, pain, sufferings, regrets, loneliness. I felt physical pain in my chest whenever he suffered. He made me laugh. He made me understand seemingly hidden reasons for his those actions that were considered unpleasant. This drama was my first time watching him. And If it was not for him, I think I would not be able to love this drama as much as I do now, without him this drama would not be as much interesting for me as it is now. Hwashin is a difficult role to play where he is an ordinary guy with an unlikable personality on paper, so the actor had the daunting task of making him as an endearing, adorable one, also actor had to show his grief and pain but not going full emotional & Melo but with a touch of humour, that is again not easy to act BUT JJS has done a DIVINE job with microexpressions and emotive eyes to fulfill all the needs of the role. I can go & on in praising him but I would like to leave a link here that would prove you how much of a good actor he is and how much of a phenomenal actor he was in Jealousy Incarnate as Lee Hwashin. Don't forget to read the comments down there in the last part of the article.
http://netizenbuzz.blogspot.com/2016/10/kim-soo-hyun-polls-in-as-1-romcom-king.html?m=1
Also, apart from his outstanding acting as Lee Hwashin , I would like to appreciate him for taking on such a difficult role where he actually had to wear a bra. A role that is actually as embarrassing to play as an actor as embarrassing it was shown in the drama for the same reasons, for all the same stigma .