The general storyline seems straight forward at first: a student falls in love with his teacher (who has been in love with her teacher for years). But it really is not a story about forbitten romance, but turns out to be the typical love triangle you've seen a hundred times. Most of the angst-moments within the story do not center around the fact, that a young student falls in love with an older teacher, but how he is interested in another man's woman. In my eyes, the female lead acts atrociously towards a student in her care without much thought for propriety, safety or basic curtesy. She entirely ignores his feelings and acts however she feels like, as if she was the student. Otherwise questionable behavior is to be expected within that kind of setup, but there should be some reflection on the right and wrong, maybe hesitation on her part, something like this to add depth to the story. I feel throughout the drama, that she just doesn't take him seriously which is an insult to his earnesty.

It doesn't help, that the second male lead is as interesting as a glass of water. Throughout the whole drama I kept wondering why on earth a vivacious young woman would cling to that weak, silent and indecisive kind of man, who does little for her and seems constantly on the verge of abandoning her. Maybe some more background story would have helped with some more key moments as to why this teacher came to be so important to her, I think what is shown does not justify her devotion. If he would have been charismatic in some way, speaking up for what he thinks is right, something to give this character some kind of profile, maybe one could relate. Puppy love is all well and may lead her to return to him, but at some earlier point she must notice, particularly as she is astutely aware of her pupils emotional situations, that he can't be what she took him for. The same is true vice versa: as he already had a girlfriend, why did he fall for a student? It lacks explication. Plus, as the situation between the relationships of all three are quite similar, there should be some reflection on it. How dare the second male lead reprimand Tae In for his love, if he himself benefits from just the same thing? The drama shows little of this conflict.
The last few episodes got better, if the whole drama would have been more like that, it would have been nice. In the middle part, the story drags quite a bit.

Then there are some scenes that I personally find disturbing and off-putting. A father who hits his son and gets him hospitalized should be convicted for domestic abuse in my opinion. A teacher who tells that beaten and bleeding student of hers, that well, he just shouldn't have provoked his father, should be sacked on the spot for negligence. Punishment of a student leading to bleeding wounds is also wrong on so many levels, how am I supposed to sympathize with such a person?

The acting was outstanding between the two leads, Gong Yoo in particular made the whole drama worthwhile (and I am not a particular fan of his). I would have liked a more 'professional' atmosphere between the couple in the beginning that changes slowly, but that's storyline. The second male lead had nothing much to recommend him. Acting and storyline both didn’t do anything for this character, even though it got better in the very end. The other characters were all right.

All in all, I thought of dropping the drama midway but I'm glad that I watched it to the end, as the last three episodes kind of make up for the drag. I won't watch it again though. There are much better stories between a teacher and his/her student...