It's Okay, That's Love (2014)

It's okay that's love is also a drama which deals with psychological problems and treatment to mental problems.
It's love story between a doctor who have a psychological problem and a male lead with illusion problems. It's like how both of them fall in love and try to heal each other.

Gong HyoJin's amazing acting takes on a different, and slightly less 'intelligent' role in The Master's Sun - but pulls it off as flawlessly as she did her eccentric and complex character in It's OK, That's Love.
Both dramas have a lead character (Joong Won in The Master's Sun, Hae Soo in It's OK, That's Love) that sees themselves as a little bit superior and doesn't want to have much to do with the second lead initially, but turns into a comedic and cheeky relationship.
Both have psychological elements to them which can be very sad. Without giving too much away, a departing of a certain soul in TMS reminded me of a soul the metaphorically leaves in IOTL). They also deal with healing wounds and fixing problems of the past.
Both are funny and feel-good dramas.
TMS is a little more slow-paced but has a more complex plot; IOTL has more side-plots, a less complex main story but is more high-intensity and high-emotion.

Both of these dramas center around a male lead with a lot of childhood trauma centered around abuse and the death of his step/father. Originally presented as cold and uncaring, it is revealed that he is extremely selfless, taking on the blame and guilt from the deeds of his family.

Both dramas center around characters with mental illnesses, undergoing professional treatment and personal care. The characters fall in love, wrestle with guilt, and mend strained relationships with family members. Although the specific disorders are very different, the dynamic between the ML and FL of "We're Not Trash" very much resembles the dynamic between the second couple of "It's Okay, That's Love."

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 dramas deal with mental health issues. The female lead of the drama is also the titular Psychologist who is also responsible in dealing with different patients with different Mental disorder. The Male lead of the drama is a novelist but at the same time co hosted a radio show. Both dramas, Male lead helped cope up the female lead's issues of their health when it comes to anxiety, depression and heartbreak. Same goes with the female lead act as a friend, lover and a doctor to ML.
Both dramas has some similarities when it comes to themes, romance, healing, mental health and many more.

Both dramas center around a Male Lead who is extremely selfless towards those he cares about, putting his own needs at less importance than the needs and dreams of his family and love interest. Male lead's attitude towards the female lead is also very similar from start to finish. There's also a heightened focus on the leads and their relationship with their found families around them.

Both of these dramas involve a prominent storyline related to the concerns of mental illness on the relationship.

The romantic leads of both of these dramas just came out of relationships that ended due to the infidelity of their partners. Due to circumstances, the leads wind up cohabitating in a house together. Both dramas also focus on the dynamics between the leads and their coworkers/friends, life and relationship lessons, conversations about marriage and life plans, and the professional backdrop of the setting.

I think The Princess' Man more heavier melodrama than It's Okay, That's Love but they all fighting for their love even the opposition from family or illness

At first, they may seem different: Love O2O, being focused on gaming and college life while It's Okay, That's Love, being more focused on psychology or healing.

However, after watching both of these great dramas, I'd say they somehow share a similar vibe, which may be because they both have:
-natural yet off the charts chemistry between the leads
-strong and mature relationship, where both sides support, respect, and trust the other person through thick or thin
-skinship and kissing scenes (or fluffy moments, in general) enough to make you root for the main couple (although IOTL is a lot better and intense on this one)
-admirable character and/or couple development (the lead/s definitely exhibit growth throughout the episodes which further helped strengthen their relationship)
-happy and satisfying ending

*there are probably more similarities, but these are all I could think of right now.

Although not as deep as It's Okay, That's Love, this drama also touches on mental illnesses with the leading male Seo Jae Hee. I also found myself emotionally invested with the lead and found myself wanting to cry when he did. Again, not as deep but worth the watch

Jung Yeol and Na Ra fell in love with each other and got married. During their marriage, they have grown to hate each other due to their personality differences. They decide to get a divorce. A month later, their divorce will be finalized. But, on the day that they applied for a divorce, they get into a car accident. When they wake up at the hospital, they have both lost their memories and do not remember each other.

Both dramas deal with the harsh realities of life and how personal struggle can lead to positive growth.

It's my second recommendation for Age of Youth as I was literally amazed, felt so good watching it.

Both have super awesome Soundtracks ( with foriegn songs).
Both have amazing performances from the actors and actress.

The storyline from both drama evolve friendship, romance mixed with some good comedy. Aside from that they are unique and different from each other in term of overall plot.

Both of these Masterpieces gets 10/10 from me. (Gladly)

Enjoy your watch :)