Both dramas are about two people who share a dark childhood. The main characters are both a police officer and someone involved in the underworld. In Ouroboros, the mains are secretly working together for revenge while in Kill It they are unaware of their shared past and are on opposite sides of a case.

Both are short films that focus on the relationship between 2 teen high school girls. The feelings and the little things people do for the people they care about are spotlighted.

Both dramas are focused on an older woman and younger man falling in love. Both relationships also begin with a mentor-mentee dynamic with the woman introducing the man into a new field of work. The guys are also artists.

Both series are about an older woman and younger man meeting abroad and sparking a romance. Encounter is slow-paced while Koi suru Hong Kong is fast-paced and action filled.

Both series are about women (who are quite oblivious most of the time) learning how to gain their confidence. They both also feature cute romances where the male lead helps her come into herself.

Both series are about women getting back into the workforce after taking off to focus on raising their families. They both have to start at a lower-level job then they previously occupied and their romantic interests are both younger men who are their superiors at work.

Both films are about a younger and older man falling in love. In both relationships, there are struggles and issues that the characters have to face and overcome in order to realize what is needed to be together.

Both series take place in Joseon and deal with the royal family and dark supernatural elements that are used for political purposes.

Both of these titles center around a relationship between a young woman and a much older man who work together. Through the relationship that is formed, both parties are able to grow and overcome the difficulties they face.

Both series are about a teacher and student falling in love. The teachers both love their job and really want to work hard and inspire their students to become their best selves but their feelings for one of their male students threatens to derail their career. They struggle with rejecting the advances of the student as their feelings continue to grow.

The main character in both series are doctors and their work is a major focus. A lot of the issues that the main characters have to deal with in their interpersonal relationships are similar.

Both series deal with an older woman who becomes involved with a high schooler. The women are unsatisfied and unhappy with their current lives and must figure out what they need to do in order to live fulfilling lives.