Two main characters in both dramas meet as kids, but when they reunite with each other after many years one of them forgets their past relationship and does not recognize the other. Both have a case of forbidden love vibe to it with the reason being same.

Both have the same vibes as the ML is taking revenge against the people who hurt him in the past and as part of his revenge sleeps with FL's relative.

Female leads in both the dramas are die hard fans of their cherished idols and would do anything for them.In Reply 1997, the lead is a high school girl while in Her private Life, she is a curator in her30s.

The leads in both cases are the spouses of a man and a woman found together in a car accident. How they both suffer from the betrayal/death of spouses , becomes each other's support and eventually fall in love with each other forms the premise of the story. While in April Snow both leads's spouses were in coma and were clearly having an affair, in If I can love you so, both their spouses die leaving a lot of unanswered questions about their relationship.

In both dramas the issue faced by the male lead is the same. In Kakafukaka the lead couple meets after many years and in Otto no Chinpo ga Hairanai, the couple is married.

Cha Soo Hyun's character in encounter is similar to Hae-Ryung's story in Happy Home. They both play unhappy, aloof but dignified daughter in laws with disapproving mother in laws. Both were married into rich family and get divorced by their husbands to let them free. Both ex-husbands love them still and want them back in their life. Even the divorce contract also is similar. Both are lucky to have a new man in their life who love them immensely.

In both dramas ,the protagonist is a high schooler who is a writer of popular literary works but keeps their identity a secret in school.

Both dramas are about the life and struggles of a single teacher in her 30s and how the arrival of a younger man in the school changes the life of her and people around them.

In both cases you have the main happily married lead divorcing her cheating husband and getting back to work from rock bottom with a handsome younger man by her side encouraging her.

In both dramas the theme is the same, a military man falls in love with the military doctor and tries to woo her in different ways.

Both involve the main character time traveling back into the past to save a friend and almost the same ending too.

Both have a vain and lazy king who is not interested in resolving issues and is forced to get married to a smart but ugly woman. He has another wife who is very beautiful and he dotes on her. Both dramas, "ugly" queens have the same red mark in their face and probably based on same story.