Recommendations

In addition to the similarities in age differences (men are older than women), other similarities lie in the characters of the main characters.
The male character is very mature, patient, can solve problems with full consideration. A mature figure who can protect the woman he loves.
The similarities between the female characters are that they are both cheerful, optimistic in living life, spreading a positive aura to the people around them, this is what makes people who know them like them.
The two male characters in these two dramas who are adults, when they fall in love, both do stupid things that are very funny like young people who are in love and their love is not disturbed by other women, very loyal to the person they like.

the 2 main leads solve cases for the government. one is a detective one is not but their bickering and banter keep you engaged

Sociopaths in love.
Murder, manipulation, naiveness, betrayal...
The ladies prevail!

Both shows weren't very well received but I personally think there's something so intriguing about just watching bad people be bad.

If you enjoyed Good Luck, you might find Eternal Rebirths equally captivating. Both series delve into fantasy-driven plots with transformative journeys that redefine their protagonists' lives. With shared tags like Short Length Series, Web Series, and compelling supernatural elements, they offer a blend of romance and drama that keeps viewers intrigued. Similarly, Eternal Rebirths makes an excellent recommendation for fans of Good Luck, as its themes of magical phenomena and second chances resonate deeply with the harem and fantasy aspects explored in Good Luck. Both series promise engaging storytelling and imaginative worlds, making them perfect companion pieces.

Both are Republic China era.

Both have revenge plots.

In both dramas FL deceived ML in the past, it was way terrible in Love Trap since she literally ruined his life. He wants revenge when he comes back.

In both dramas FL is engaged to ML´s nephew.

Both dramas have angst and heavy tension.

ML asks FL several times if FL ever loved him in the past.

Both are second chance love-stories!

Although MC´s met as children in False Face.

Both characters are deadly and can fight and use guns. In False Face, FL wants revenge towards ML, while ML wants revenge towards FL in Love Trap.

Both dramas are heavy with angst and sexual tension and hot kissess.

In both dramas FL is a secret agent working for a organisation.

There is a case of if FL is able to kill ML in both dramas, both ML gives her several chance in shooting him.

- second chance romance
though a little different from this drama's premise
-leads dated in college but something happens and they have to seperate
now , they reconcile their relationship

- LGBTQ+
- Police and forensic characters
- dark
- crime & murder that needs to be solved
- Max is in both

- Visually similair
- annoying SML who has crush on the FL and turns evil
- FL and SFL don't like each other at the beginning
- Wuxia
- "decent" cgi

This is a combination of The Penthouse and Battle for Happiness

Revenge
Love
Drama
Same mystery death
School

Both have a college setting (for 2 of the 4 leads in Knock Knock, Boys).
Both have fairly simple stoty lines where the friendship between the leads is as important as the romance.
Both are charming and show healthy relationships.

Similarities
- Mr. Gu and Jang Chul Min have similar personalities, and that is the same with Ha Jung Hwa and Yeom Mi Jung.
-Both film/show can be a SLOW burn
-Both stories are focused on the mundane parts of life
Differences
- Ha Jung Hwa is blind and has a positive outlook on life. Jang Chul Min is tired of her mundane life, and is a bit of a nihilist. (Still love her tho)
-My Liberation Notes is focused on family, and Always is focused on romance
-My Liberation Notes has a happier ending than Always
If you like My Liberation Notes, you'll probably enjoys Always and vise versa!!

If you enjoyed watching Love in the Desert, you might like Zen Di Ta Qian Jiao Bai Mei. Both romance dramas with Fang Yilun (Alen Fang). The later is a romcom. :-)

Similarities-
-Mr. Gu and Kim Ji Won have a similar romantic dynamic as Nam Soon and Dong Hyeon. Both are opposites yet are very sweet to one another.
- *mini-spoiler* Mr. Gu and Nam Soon is a gangster/land-shark
-Both stories are about showing the slow and mundane parts of life
Differences-
-My Liberation Notes is focused on the Jung family, whereas, Pain is about Nam Soon and Dong Hyeon becoming a family with each-other.
-Dong Hyeon is sickly whereas the sisters in My Liberation Notes are healthy.
-Pain is much more of a romance than My Liberation Notes
-Dong Hyeon is much more extroverted than Kim Ji Won
I honestly think anyone who likes Liberation Notes would really enjoy Pain, and vise versa.

If the aspect of Strangers from Hell you liked was the dark connection between the two leads then Somebody is definitely for you. Both have two MC's (FL/ML in Somebody and two MLs in SFH) who are not all well in the head, one of them (in Somebody it's the ML) is a killer who becomes interested (obsessed) with the other (FL) due the fact that they find a certain kinship in each other. ("I know that you're just like me and I love it." kind of vibe.) Both endings are relatively the same with the MC killing the other and being irrevocably changed by them.