This is one I binge watched throughout. Its so good, the OTP's chemistry was amazing and they were pretty adult about it. I loved So Ji Sub in this (even though he looked like a hobo half the time which is not surprising for a trainer) and Kang Joo Eun was pretty even in her fat suit. The comedic moments in this was spot on I definitely laughed out loud several times whilst watching this. I loved all the characters in this specially puppy like 'kids'. The story itself was quite straightforward and I loved the overall message of living a healthy life. It inspired me to take up jogging. Nothing really stood out in terms of OST but the cinematography and editing made the show flow quite well. Definitely worth a rewatch. Don't hesitate.