One is a movie and another is a series.

Both of the leads have an occupation in which you can rent a person.

In RaF, it's only for the purpose of being a friend for a day.

In Rental-san, the main lead can be rent for a specific task which requires to do accompany a person in doing a specific task (see more: description of the drama). Rental-san is based on a true story too.

Both leads are expressing their fight for independence through various literary forms.

Both are set during the Japanese occupation in Korea.

In THoD, the romance is highlight between the leads, but in DJ, the friendship between the leads are much more showed.

Both are sad and based on true stories. (As it is indicated on the tags)

Both dramas feature couples who started their romance in a guesthouse! WHY is a webdrama though Eulachacha Waikiki has funnier scenes since it's a cable drama

Tay and New are the stars for both.
Basically, TayNew Meal Date is an eating variety show.
A talkative side of Tay is also shown!

Both of the couples have some amazing chemistry!!!
For both dramas: before dating, they dislike each other for specific reasons, but in TWM, one of the leads has a girlfriend.
Too much spice in every episode!!!
Both dramas show campus romance, friendship and characters are charming too!

Both have the same dating style and story development.
Both male leads are working at a high ldvel of management position in their offices.
Plus both ML are good in showing two sides of their attitude

Both are inspiring movies related to brass band. Both also have a motivating and well-developed lead character.

So similar when it comes to the health conditions of the leads. But in Millionaire's, the female lead is the one who's sick and they both hid it from their lovers at first eventually leading to the sad part .

Golden Child is the cast in this movie. It is related to their comeback song, "It's U" *released this January 2018* (their first comeback after their debut song "Damdadi" which was released on August 2017)

There are Japanese, Chinese and English versions on Woollim's channel on youtube!

A pre-debut variety show for Golden Child.
This show came before "Ring It!"
It has subbed episodes on their Vlive channel.

Not really similar in the plot but the cinematography, romantice vibes, warm smiles and OSTs (important factor seriously they are all GOOD!) are some of the common traits of these dramas.
Plus, their chemistry might get you screaming!!!
Also, both male leads have careers related to arts.

Both movies involve time traveling, but in Akko's Secret, the elementary schooler becomes her future self and.... wait for the surprise in the end! :D