Recommendations

Both leading actresses give off the same vibe. Similar message and theme centred around the relationship between the two main characters- and how the man's 'condition' affects that relationship.

If you are a psychological/romance film fan, then you should definitely check out both.

If you don't mind the language difference, then try this drama too: Marry Me, Or Not.
The similarities are as follows:
1. Male lead not wanting to marry and wants to live alone
2. Male lead using female lead to achieve his want of staying single
3. From fake relationship, the couple learned to love and value each other and turned false relationship to true love
4. Old couple in verge of divorcing, who communicates through sticky notes/boards/cellphones
5. Male Lead's Mother against Female Lead and prefers to have an obedient daughter-in-law
.. also, the couples in both dramas have great chemistry. They'll make you feel giddy inside. For Rom-Com Fans, this is a much watch.. very light, romantic and funny story.

Both dramas are refreshing and both deal with different aspects of life rather than only concentrating on the main couple.

Both male lead's personalities are similar and the stories are the same premise

Both of them are based on manga and have marriage as a main topic.
However, the main leads personalities are very different.

Both of them are based on Josei mangas. While "Please Love the Useless Me" has a more funny approach, "Hapimari" is a bit more serious. Both of girls are in a difficult financial situation and the main lead help them.
Also, Dean Fujioka is the main lead in both of them!
Enjoy :D

Also by TVN, these two dramas are so similar in how they don't follow typical romantic drama stereotypes and aren't afraid to push the boundaries. Some common actors for both. Nice comedy and quirky romance with really engaging storylines that don't get old.

If you like this, you will definitely enjoy Marriage Not Dating!!

both films are pretty bizarre, with crazy yakuza and a charismatic main character, also the same director (Miike)

The story of this show is about the unifying of the three kingdoms ( Goguryo, Baekji and silla). By the way the actor who plays the role of the main character is the same actor who played the leading role in dae jo yeong >>> ((Choi Soo Jong)).

If you liked king gwanggaeto then you'll absolutely like this show .

both of them are based on a true story of a man who has the dream to do something great for his nation.

In both shows we can see fatherless main leads, who travel back in time in order to learn about past. Both shows contain romance, but Time traveller 's ending is more bittersweet(or just sad).

both about a slave who has ambition to be free and put his name in the history.

Both feature mystery in a form of a game. The Liar Game just includes stakes.

While the plots are different, Sakurai Sho plays in both of these dramas as very similar characters. Both characters are eccentric and have very similar mannerisms and catchphrases (Iiii neeee~ vs Nantsutte~) and both have dark secrets they are hiding. If you liked Sho's character and acting in one, you will enjoy him in the other.