I started watching this drama because of the typical story: a secretary, a bastard boss and so on.
I ended up laughing like crazy because of the ML manners, the way he talks, the way he behaves (when he lifts his leg to open the bin, come on!!). And the FL suddenly becomes a new person who is not afraid to tell what she wants because she thinks she's running out of time. That wonderful episode when she goes to his house and hits him with onions? That was pure gold! What I mean is that there were several scenes which I didn't really expect to watch, so they ended up being the best ones.
I also think that there are things which could have been better because, from my point of view, they ended the story too fast or didn't focus in important things. The way they solved everything in the last chapter was a little odd. They decided not to deepen in the character's relationship. Everything was packed with everyone's goodwill. Why didn't they allow us to see what happens with Shin-A's dad and friends, for example?
In any case, I liked the drama and I laughed a lot! The music, especially "I'm crazy", was wonderful. The acting was very good, specially for the ML lead, who I think did an amazing job.
I recommend you watch it, since you will laugh a lot.