This drama really takes you on an emotional journey. There are a lot of humorous instances interspersed with the sorrowful parts. I found the scene where the friend appears wearing a penguin suit and meets Soo Ah to be particularly amusing; it had me laughing out loud. I've rewatched it repeatedly, about ten times in total. It was genuinely hilarious. The moment that affected me most deeply was Ji Ho’s speech at the school event—I couldn’t stop crying. That young actor, Kim Ji-hwan, deserves a lot of praise for his work! Every member of the cast delivered excellent performances; So Ji-sub, Son Ye-jin, and Lee Jun-hyeok were all exceptional.

Source on TMDB