THIS drama is truly a masterpiece. it has EVERYTHING that viewers want : comedy, action, thriller AND romance.
the romantic scenes are just so well done they make you all bubbly and frustrated inside, that you'd literally be screaming alone in your room.
THE ACTORS THOUGH, lee jong suk has always been one of my favorite actors, alongside with ji changwook. he acts so DAMN well wether it's with his face or body. his facial expressions really transcript his feelings. not to mention that he's so fucking handsome, like come on (and he's 185cm !!!!).

han hyo joo is such an amazing actress as well. i really love her and her way of portraying her character. she doesn't annoy you and she does not whine when she's talking, which i find extremely important.

and don't even get me started on kim eui sung, this guy really needs to earn i don't even know how many awards. he's SUCH AN AMAZING actor. i really mean it, i hope you'll enjoy his acting skills as much as i did !

the plot itself is so well thought, there are NO plot holes and everything slowly makes sense leaving you wanting for more. the story is so unique, i swear to god. the synopsis of this drama doesn't even represent 1\10th of it.
the cinematography and editing in this drama are incredible, i'd say excellent even perfect.
there are a lot of transitions between the two worlds and they're just- so well edited. i always get impressed everytime they come on lol.
AND THE MUSIC ! i reallYYYyYYY love the background music (not the ost), of course i love the ost too but the background music really sets a mood.

all of this to say that i have rewatched this drama 3 times by now, and i will continue watching it lmaO. (first when it came out, then in december of 2016 and now in september of 2017).
there are a lot of people who complained about the repetition and flashbacks of certain scenes, but it's part of the story !!!! if you're going to complain or whine about something so little, maybe you shouldn't even be watching dramas in the first place.