Yumi’s cells as I describe it as an adult version of Inside out. It’s very funny, shows a lot of tropes but is not tired and has an interesting take on a love story. I think it’s a gentle introduction and is to relate to as it’s a romance.

Oh no. No no no no. ONE DRAMA?! How could you do this to me (and many others, I'm sure) @missvictrix?! I didn't want to answer this question, but I'll be thinking and rethinking about it for weeks if I don't give an answer now. So here goes...

GOBLIN. It's funny, romantic, exciting, heart-wrenching, epic. It's not perfect, but it's a very strong gateway drug, er, drama.

It depends on their time tolerance to new things:

If it is a movie, PARASITE

It depends on the person.

If it's a romantic open person, I can advice a very Kdrama-esque drama with tropes, beautiful leads, good kiss scenes ;

If it's "just" a romantic person, I would choose something more slice of life to turn down the Kdrama-esque side ;

If it's someone who doesn't like romance and more interested in action or darker story, I would choose more like an OCN/Netflix/Disney drama.

King the Land.

1. It is recent.
2. It introduces the tropes and then some, and so if the person likes such things...they're definitely in for a lot of fun as they get into more dramas.
3. It's got romance, lots of comedy, and some seriousness--but not too much seriousness, like "nature of the human experience" serious.
4. K-dramas often have "that one weird thing" that makes you really scratch your head...KtL minimizes that weirdness to secondary characters.
5-∞. Junho.

It has to be Crash Landing on You. It's the quintessential rom-com, and it was a blockbuster hit, so they may have heard of it or know someone who has watched it. (But personally I never recommend K-dramas to people or try to drag others into dramaland.)

Descended from the Sun because it is the drama that got me back into Kdramaland.

I think it's very fun and swoony to watch. The OTP and the second lead couple are worth rooting for. Cinematography is gorgeous. I think it is one prototypical Kdrama.

Taxi driver 2
Because:
1. The story is catchy and easy to follow.
2. Quiet male lead but not the weirdly quiet type. He speaks and does so eloquently when he needs to.
3. The male lead is good in actions. A bit too good that it enters the territory of superhero but that’s what makes it addictive.
4. Smart and brave female lead.
5. Endearing supporting characters.
6. Humour done right. Not too gory. Happy ending for main characters. Some hint at romance.
7. No toilet jokes.
8. If one is interested enough, there’s season 1 to binge and season 3 to anticipate.
9. If one is interested in the male lead, there’s Signal to dig deeper into Kdrama land.
10. After Signal, the rest is history.

To hook my friends, I try narrating or showing clips of swoony scenes, but none worked. I later realized that no amount of persuasion would work until and unless people discover the fun in kdramas by themselves.

Recently, one of my friends asked for K-rom-com recommendations because they were bored with the other language offerings. Guess what she chose? Bora Debora . A drama that I did not suggest and dropped at Ep 1. I warned her that it had criticism on the behaviour of the female, but she enjoyed it so much that she completed the drama within a week.

To conclude, it is much easier to recommend dramas to people who are already K-fans than to get a person into this field.

That's tricky, because it depends on both the specific genres that people like as well as the availability of any given show. As someone who doesn't typically seek out romances, I'm not sure I've have ever entered dramaland if the first recommendations I'd gotten had been typical "gateway" shows like Crash Landing on You or Boys Over Flowers. I'm also guessing newbies won't want to put up with ads or subscribe to drama-specific sites like Viki. My first instinct would be to recommend some of my favorite sageuks, since that's what got me into dramas, but none of those are currently available on "mainstream" sites. Therefore, based on what's currently on Netflix and assuming the person shared similar tastes with me, I'd probably go with Stranger, My Mister or Beyond Evil. They're all shows that feature great acting, writing and directing, and are pretty accessible to someone who's never seen a Korean show, although they won't work for the folks looking for breezy, sweet, or swoony.

So far, I think five people around me have started watching kdramas. And depending on the type of person I either recommend ‘Stranger’ or ‘Weightlifting Fairy/CLOY’ or both.
Both have had high success rates.
My follow up drama recommendations will depend on which one they liked better. My dad loved Stranger and I recommended ‘My Ahjushi’ and he had since become a IU fan 😅.
Other dramas recommended were Vincenzo, Extraordinary Attorney and Hyena.
For romcom, there is a lot of options.

I know a lot of people got hooked on CLOY and became kdrama fans during the pandemic. That would be my recommendation. Goblin is too heavy to start with, but obviously, my favorite.

Our Beloved Summer
Twinkling Watermelon
18 Again
The Matchmakers

For romcom lovers: Boys Over Flowers, Crash Landing On You, Coffee Prince, Goong, Full House, My Name is Kim Sam Soon, King The Land.
For melodrama lovers: The Four Season dramas (Autumn in My Heart, Winter Sonata, Summer Scent and Autumn in My Heart).
For legal drama lovers: Extraordinary Attorney Woo, Juvenile Justice, Stranger, Attorney Shin, Innocent Defendant, I Hear Your Voice, Law School, May It Please the Court, Hyena, The Good Wife, While You Were Sleeping, Punch).
For medical drama lovers: Romantic Doctor Kim, Hospital Playlist, Daily Dose of Sunshine, Good Doctor, Doctor Prisoner).
For thriller-lovers: City Hunter, Moving, Vincenzo, Taxi Driver, Healer, Kingdom, Signal, My Name, Mask Girl, Happiness, Flower of Evil, Through the Darkness, Mouse, Save Me, Nobody Knows, Voice, Tell Me What You Saw, Blind).

I would recommend Healer due to being a drama that is as close to the westerns one that I have seen. It is action packed, good romance with a happy ending, great backstory with enough mistery to keep you hooked and other elements that are familiar to the majority pf non k-drama watchers. The korean traditions and customs are not the main focus, those are things that will draw them out because of not understanding or not being familiar with. Of course, for someone like me, those things attracted me more, but I know, from talking to many around me, I am an exception and not the norm.

It depends on the genre.

Do you want fun? Mr. Queen.
Do you want heavy social commentary? Life.
Melo-romance? You Are My Spring.
Rom-com? Business Proposal.

It all depends on the genre.

Crash Landing on You. It's not even my favorite or even in my top ten. However, it is a good introduction to kdramas as there is romance between two beautiful people who are good actors and a small town feel (the North Korea part is the best part of the drama IMO) which shows the longing of the "simpler life" (before subways or Subways) and sense of community. CLOY has a lot of elements that are hallmark kdramas (the production, the fashion, the relationships) that if you like them, you can delve deeper in other dramas that explore them more fully.

Lately I think that one drama would be Mr. Queen!! Its very clever and full of comedy! Its a whole package, also is a good gateway to sageuks! Also whoever I have recommended it to, have thoroughly enjoyed it!

Otherwise I would recommend something from the many fantasy dramas that Korea offers- Master's Sun/Legend of the Blue Sea/Mystic Pop Up Bar/My Girlfriend is a Gumiho/Arang and the Magistrate/ - because those are unique to Korea.

Can't go wrong with few classics- Coffee Prince, Kill Me Heal Me.

Like Flowers In Sand! It has romance, mystery, coming of age, slice of life, and sports drama tropes, all mixed in a glorious way. And it is 12 episodes.

Under the Queen’s Umbrella.

It depends on the person and what he/she likes.

Sageuk Action Comedy - "Flower That Blooms At Night" It's simple, sweet, and short.
Slice of life - "Age of Youth"
Rom.com - "My Love From The Star"
Thriller - "Beyond Evil"
Weekender - "What Happens To My Family"
Melo - "Just Between Lovers"
Satire - "Heard It Through The Grapevine"
Medical - "Doctor Romantic"

Oh, easy. You From Another Star. It has beautiful actors, the most adorable heroine ever, interesting plot, zingy dialogue, tons of comedy…but, more importantly, tropes galore to “inoculate” newbs from the start. Like for example, the newbs need to understand that romcom will always feature a serial killer / murderous villain, a “fateful” story set in Joseon, SML doing nothing much except pining for our heroine, being absent for a number of later episodes and suffering amnesia, confusing or unclear ending, tonal shifts, tons of hospital scenes, a funny family that is actually very dysfunctional, White Truck of Doom, damsel in distress with many savings, copious amounts of drinking that moves plot along (such as confessions and flying objects), chicken-and-beer, fan service shower scenes, face-slapping scenes, somehow becoming “fateful neighbors” in a city of 10 million people, forced cohabition, noona-esq romance, fully clothed sweater-swaddled bed scenes, a very young-looking main lead who’s a loaded real estate tycoon but you couldn’t even tell, tons of PPL, evil rings, evil cue music, tons of PPL, loyal butler/sexretary/lawyer, tons of PPL, childhood connection, seaside trip that makes it known to all of us the couple has become official, time-jump-separation, main lead who knows and can actually do anything, wrist grabs, reincarnation, doppelgängers…

In words of Stefan, IT HAS IT ALL. The only thing it goes light on is Noble Idiocy but let’s spare our newbs’ immune system. That one is too much to handle from the start.

I have recommended "It's Okay Not to Be Okay" to anyone whom I could make listen. But I agree with @kurama : It depends whom I am trying to drag in.
But what I really think is a help for a newbie is the Bingocards, actually.
They make it fun to find the tropes, and you get to feel "in on the joke" from the start.

Only one?! The angst!

But in the end I think I would have to go with Healer. It's a full package. Romance, action, traditional kdrama elements of birth secrets and corruption and an awesome power couple to top it off. I've never heard of anyone not loving Healer.

Bulgasal - excellent casting, very suspenseful & thrilling and full of romantic tension between leads yet still family friendly with a warm found family you don't want to say goodbye to. I watched this for Lee Jin Wook (Voice 2&3, Goodbye Mr Black) and he is glorious here. Also became a big, big fan of the female lead Kwon Nara. She is so charismatic and graceful and emotionally delivers. There is emotional truth in her acting. This is something that is very important to me as a viewer and not something all actresses are capable of bringing to the table.