Kdrama OSTs are a very important element of drama watching as per me and CWPFN seems to be having an amazing OST. 

My faves are Kim Greem's "I want to sleep in more " and Klang's "Gravity"..The former has some of the best lyrics about a love you can't give up or deny despite trying and gels well with the overall theme of the show

What are your faves ?

✔I love you love by Yoo Seung Woo

I love the beat and it makes me want to dance .. his voice sounds like Lee Jong Hyun from CN Blue in this song...he has a beautiful voice and sang songs for other OST's too 

https://youtu.be/wlPd4jSRorE

✔ Gravity by Klang

It is upbeat and happy song