Easily like a Colgate ad it features people smiling 90% of the time, and that's maybe the biggest charm it has.
Look, I was going through a rough time, all angsty showering and stuff, so I decided to watch the easiest, happiest, corniest drama out there. And I found it; All About My Romance has no plot, no conflict, no underlying themes or nuances - it's just good people goofing around and being cute around one another for 16 episodes. Literally everyone ends up coupled, the OTP is together by episode 5 even.
Granted, Shin Ha-kyun is THE draw for me, hands down, I believe anyone else would've been dull, but he managed to give depth to his character and by extension, the drama.
So yeah, if you want to feel warm and fuzzy inside, go for it right now.