PROS:
-Effective cinematography and shooting styles, I also love how the changing four seasons is shown throughout. The accompanying OST are wonderful too.
-Beautiful lines and quotes, among my top favourites:
Ep1: The rainy day that disappeared, I really want to get sprinkled again
Ep 5: If time can be suspended, I hope they will always be my good friends, the kind that never leave
-Green flag characters; the main characters in this show have positive outlooks and actions in their life
-Female lead Su Zaizai is one of the female lead with most positive attributes in Cdramaland - bold, cute, kind, chivalrous, brave, able to stand up for her rights and help others in need, and more mature than what her energetic personality suggests. Her sunny disposition rubs others in a heartwarming way(including the viewers such as me).
-Male lead Zhang Lurang is an introvert but unlike negative introvert characters in the past, he's reactive to Su Zaizai's advancements, it's a two way arrow. His little smiles which keep growing by the finale is adorable to watch.
-The 'squad' of 5 is adorable, their friendship gives off a special feel to adults like me, something that I may once feel back then in my schoolyears but get lost in time as time goes by and adulthood takes over. One of the most effective friendship scene where I shed my tears is when Su Zaizai found the rest rummaging the trash to help her. Great shots, great emotions felt without much dialogues or exaggerated emotional outputs.
-There are not much about the family members, but they are nicely depicted to show how Su Zaizai and Zhang Lurang grow into their sunny vs introvert characters. Other than that, Guan Fang's grandma has some of the subtly emotional scenes of the drama, and I also feel for Zhang Luli. His talk with Su Zaizai tugs at my heart.
-There is no prolonged third parties or major incidents in the storyline, most issues got resolved within 1 or 2 episodes.
-24 episodes at 30-min runtime is just nice, the pacing is comfortable for a leisure binge or daily watch

CONS:
-The female lead might feel too shamelessly into the male lead in the first few episodes (it gets better as male leads reaction gets more obvious and more of female lead's positive personality shown from episode 5+)
-Storyline is generic and lack of dramatic twists and turns in the plot, it's a flat slice of life drama about some kids growing up into adults, full of youth romance tropes
-The romance is innocent, even their kisses at the end feel innocent though sweet, there are no steamy romance and intense sexual pleasure
-There is not much details towards some other characters and sub lines in the end, such as Zhang Lurang's parents
-Their daily school-college-work life feel too idealistic and gave off a dreamy vibe, lack of touch with realism

OVERALL:

It's a story of a little sun and a sunflower finding and 'flying' towards each other. Must watch if you like coming of age genre with an innocent, pure young romance done exceptionally well. One of the best in this genre. Stay far far away if you want intense romance, dramatic issues, dark characters, tragic events, harsh reality...