In both dramas -
- CEO and Employee Romance
- Rich ML and FL's family runs restaurant
- Sweet story of Second lead couple
- ML falls first
- Hardworking FL
- Main FL and second FL are best friends
- MLs are traumatised by Rain
- Some romantic scenes in common
- Main ML and second ML are brothers/ brother like

Both have Bullying and Revenge.
Both have Bullying in High School.
Main Character of both dramas use their tactics for revenge.
Both dramas have abusive parents.
Both have violence and abuse.
Main Character of both dramas have same personality.

—Both dramas have older FL and younger ML.
—In both dramas FL is teacher and ML is student.
—Both dramas have teacher-student relationship.
—In both dramas FL wants her reputation back.
—In "Why Her" ML and in "Melancholia" both leads have painful past.
—MLs from both dramas have previously worked together in another drama "18 again".
—Both dramas have romance and drama genre common.

In both dramas three best friends, Each pursue different paths in both career and love. Despite life's difficulties, the three friends can always return home at the end of the day and support each other.