The plot gives precious lesson for married couple, children, and parents.
For children, sometimes they feel that thir parents abandoned them, not giving much attention, but actually they really love them, but some of their actions are 'backstage', without them knowing. Also when they was kids, they don't know what did their parents do, what did they sacrifice for the sake of their children. Every single thing from a child is special for parents, even simple things like the first word they say, the first time they can ride a bike, first day of school. It's all precious.
For parents, maybe they won't understand their kids as well as their friends (portrayed by the main lead of this drama Hong Daeyeong), kids often hide their secrets and try to face it theirselves.
For married couple, it's important to maintain communication, or everything would be misled. This is the general message I got from this drama.
My heart can't stand the heartfelt scenes, especially the main couple's journey at the beginning of their parenting life. I looked at my parents after I see them, because I feel generally all parents did the same. Everyone should give this drama a try.