1. Bickering couple, Enemies turn into lovers.
2. Relationship between celebrity and non-celebrity.
3. Leads cannot readily express love though they love each other.
4. SS has multiple couples while FH revolves around one couple.
5. No toxic 2nd ML and FL in SS. But in FH, yes there are.
6. Both have an eccentric and lovable male lead.
7. Both are super hits of their contemporary time.

both have-
1. strong bonding among three female friends and they were connected since school days.
2. one friend is terminally ill.
3. three couples.
4. one friend is kinda timid and feels insecure in their friendship.
5. 39 has more subplots than NWABU.

1. three sisters bonding.
2. both dramas have multiple cute couples.
3. the drama GD has an aged couple like the aunt and Mr. yang in the drama Once Again.
4. GD has two funny brothers set like the Yoon brothers in Once Again.
5. GD also has a strange mother character like Gyu Jin's mother in Once Again.

both dramas give a healing, peaceful vibe.
both have nice countryside locations.
in both dramas leads were connected since childhood.