Both dramas look back at past relationships, there is a constant switch between the present and the past. In both dramas, the leads started their relationship in high school. However, since then they have moved on and gone their separate ways, finding new paths in life. By coincidence they meet again years later and restart their relationship.

Both dramas have similar genres (melodrama and romance).

Both dramas have a similar style of comedy despite being in two different settings. The Forbidden Marriage is set in Joseon while A Business Proposal takes place in modern day.

Both the female leads start by deceiving the male lead into thinking that they are someone else, but end up falling in love with them.

Overall both dramas have a very sweet (and slightly spicy) romance

- the dramas center around survival. happiness is about surviving a zombie apocalypse, while d-day is about an earthquake
- they focus on themes such as human greed, morality and selflessness
- both dramas have mainleads that work together as a duo and later become a couple

- Both female leads are strong and fun
- Both male leads are caring and know how to smile!
- They're both based on a webtoon
- Combines romcom elements with a bit of crime
- Similar fresh comedy style