I was desperate to watch something new at the time and I never thought I would like this sort of drama since it plays in an office/firm and has a lot to do with business... But I never laughed so hard and so much because of one series. The comedy is intelligent and not cringy like in usual sitcoms. There is almost no romance present, though, but I'm happy it turned out like that! The Bromance in this is strong  and I really was a huge fan of that!
Story:
The writing, how the plot was playing out and how they made a construct of problems and obstacles only to make the character's find a solution which is even more amaizing, surprising and especially: clever!; is what made me being glued to the screen.
Acting:
The actors... don't make me start on them! They did an amaizing job! The acting, especially from Nam Goong Min, captivated me to the extend that I forgot everything around me. Nam Goong Min did an amaizing job of delivering the comedy through facial expressions, way of talking and simple body movements (I have a folder on my computer which is Nam Goong Min's facial expressions only, I swear)
Music:
I don't remember the music that much but I remember that the athmosphere was captivating and on point throughout the drama. The music plays a huge role in that aspect and that's why there is nothing to complain about ^^
Rewatch value:
I can 100% see myself watching this drama again to enjoy the cleverness, unique acting and the overall feel it has!
Thanks for that drama!