Most of my drama choices if not all are cast-based or recap-based. To name two...

...Lee Seo-jin : Marriage Contract. I had just finished Times and I just had to watch something with him inside. I remember a beanie say he was in Marriage Contract. Since the drama was already on my radar, I watched it and ended up staying also for the story.

Second is Yoo Jae Myung : Vincenzo.

My current favorite oppa is Park Seung-geun from Memorials: I still fell in love with this handsome, beautiful oppa guy. Then he's on Private Lives and on On the Verge of Insanity.

Hahaha, happy to see Kim Jae Young's face. He was also my draw towards Secret Boutique. XD

Recently, it was Kim Dong Wook in King of Pigs. I saw the creepy, scary posters, but I didn't care. I did not know how bloody or violent it would be, I was going to watch it for him. Maybe due to the years of watching crime dramas, I handled the violence ok. The whole story was brutal, tragic, and gripping to the end.

I checked out Through The Darkness because of Kim Nam Gil. I wasn't sure of the tone and how this crime/mystery drama would be, but it was excellent. Subtle, thought-provoking. A slower pace than the typical ones.

Reply 1988: I had started 1994 and could not get into it so decided to avoid the series but then found out Park Bogum was in 1988 so gave it a go and the rest as they say is history. It’s one of my top 5 dramas.

The Producers: i was looking for dramas Kim Soohyun had been in that I hadn’t seen and that one came up. I loved it from episode one it’s my sort of humour. At one point, a male idol was running around being helpful and Cindy asked him why and he said, when he was a rookie they gave him the nice boy concept and now he is stuck with it because he didn’t know any better at the time! I immediately thought of Park Bogum! He did a cameo appearance hosting Music Bank.

Let's just say it's not the oppas that attract me to specific dramas. There are so many non-oppas to watch that I mostly decide what shows to start based on the plot description, the writer's & PD's track records, and simply how much free time I have that day.

A Piece of Your Mind only for Jung Hae-in. The premise didn't sound super-appealing, but then I really enjoyed the story and the side characters - except for Lee Ha-na as Soon-ho. I have never felt such contempt for a drama character as I did for her by the end, but it was still worth watching overall.

I guess I will sit this one out. I never have a "current favorite oppa". I just add actors to my "good actors list", and they might in time upgrade to "favorites list". And yes, I do choose dramas based on the cast, but I won't finish a bad show for one actor. So, anyway, that's it.

I experienced this twice with Namgoong Min's projects: Chief Kim and Hot Stove League.
I didn't expect Chief Kim to be so funny considered comedy dramas have never fit my style. But i think Stove League is a perfect example in this category for me. I know nothing about baseball and only came solely for Namgoong Min. One of my best decision because it's now on my top 10 favorite dramas

Move to Heaven also fits because i came for Lee Jehoon but fell in love with the story. I cried a lot but it's a good one

I have far more unnis I'll start a show for than I do oppas but to keep in theme I'll freely admit that I started Human Disqualification for Ryu Joon-Yeol's luscious locks and then just... stayed.

I'm not a melo fan generally but dayuum did this drama strike a chord in me. It was slow moving but the characters were both so emotional yet vacant at the same time and watching them make tiny spaces for each other really was just a marvel to watch.

Alchemy of Souls, although halfway through 3 and not entirely sure I’m staying.

After watching our first few dramas (tabong+family) we searched for other shows starring the actors and actresses we liked. For example, Love Story in Harvard (we came for Kim Tae Hee unnie but stayed for the story).

But when I started to watch dramas alone I just watched anything. I like almost any genre, so I don't read synopsis or search the cast. BUT when it comes to my favorite oppas and unnies it's totally different. I say I'll watch the show for my oppa/unnie even if it isn't true. LOL

I was going to watch this new show with Eun Bin unnie (lawyer something) just because and then I saw a poster with Ki Young oppa in it and I was like "omg oppa is back, I'm so going to watch this show" as if it was the first time I heard about the show or something 😂
One time I was rewatching W and I saw Ki Young oppa and I was like like "omo, he's in this show? good thing I'm rewatching it". Same thing happened with Master's Sun. I didn't remember Seo In Guk was there. LOL
But...

After Flower Boy Next Door I feel in love with Yoon Si Yoon, so I watched The Best Hit (Tabong!!), Psychopath Diary, Romance full of Life, Train and It's Beautiful Now. I would've watched those shows even without him, but I got more excited of watching them because of oppa. Same with IG and KY.

I fell for In Guk after Hello Monster, then I watched Shopping Wang Louie and Squad 38. I totally recommend these shows btw.

Kang Ki Young oppa was love at first laugh. I watched Oh My Ghostess because of Seul Gi unnie, but after that show I became a hardcore Ki Young fan. Uri oppa really knows how to pick projects: Terius, Tunnel, At 18, W, and WFKim Bok Joo are such good shows!

I also have a "stayed for the oppa (only for the oppa)" experience. I finished Let's Fight Ghost only for him and David (Chong Ran x In Rang) the second half of the show I didn't care about the leads, only the bromance.

Oh, I did watch a variety show because of him and only him, tho.
It was fun! Ki Young oppa is hilarious.

Technically not Oppa as I refused to have an Oppa, I just prefer some actors over others. Here are few.
D.P.: I started the drama because of Jung Hae in and stayed for everything else even though subject matter is not my cup of tea. I tend to avoid violence and torture. It is not happy ending, you left unsettled and that’s what drama wanted and it makes 6 hours spent watching it feel worthwhile.
Happiness: Started for Park Hyung Sik. I did not even watch the trailer so I had no idea what I was getting into. If I knew, I would have never started it. Pre-covid I would have never believed in the story but only after living through Covid, I could digest it. I was not keen on living it through drama second time but drama made me do it.
I will find you on beautiful day: I started this one for Park Min-young and Seo kang jun but stayed for story and the atmosphere. Drama about winter never felt so warm.

Most things with Lee Jong-seok... Romance is a Bonus Book blew me away - it's probably my favourite drama - but I pressed play because of him. (And W / I Can Hear Your Voice both pleasantly surprised me)
Hospital Playlist - the perfect cast was what drew me in.
Also 25-21. Not going to lie, I was there for Nam Joo-hyuk to begin with. Still kind of am. TT_TT

Variety show rather than drama, but I watched Busted 2 because of Lee Seung Gi. However not even LSG was enough to make me finish Busted 3 😅

I quite often will pick something straight away after up by the same actor if I liked them in something - eg I watched part of Doom at Your Service and wanted to see more of Seo In Guk so I watched Hello Monster (which was excellent) and Shopping King Louis (which took too long to get going and was about two episodes too long for the story at the end, but was good in the middle).

Most of my drama choices are based on writer and story first, then the director and personal taste or interest, and THEN cast, and it becomes a combination of how many of these different boxes it checks that make it a watch or avoid.
Or else the choice is random, or based on external factors (boredom, need something to watch, etc) and doesnt follow a hard rule.
Much more like @lordcobol in that regard.

I'm genuinely trying to think of something I only started for the cast check box but ended up liking the story of anyway... Usually it's the opposite: I start for the cast alone, a weak start by my normal watch factors, and predictably, the story is terrible and I hate watch or drop; cast is rarely, if ever, enough alone for me to keep watching.
(Masochism on the other hand... 🙄)

Never have, never will

Gong Yoo & Park Seojoon were the first leading men I encountered at the beginning of my kdrama journey (with Goblin being the first drama I ever watched and Secretary Kim being the third) so I went into both Coffee Prince and Fight for My Way purely because I couldn't get enough either of them but I ended up falling head over heels for the cast & story.

More recently the case for me has been 'went in for the oppa, ended up discovering & staying for another one instead' - watched Extraordinary You for Rowoon but stayed for Lee Jaewook, same with 30 but 17 (AHS was the hook, but Lee Dohyun became the anchor) and King The Eternal Monarch (sorry LMH but Woo Dohwan had my ALL of my attention).

Son Sukku in My Liberation Notes : I love everything in this drama. He picked a really good drama
Choi woosik in Our Beloved Summer : same reason.

The first drama I watched because of the "oppa" (I am much older than him so he is not my oppa per se) was Pinocchio because I liked Lee Jong-suk in I can hear your voice. The first drama I watched because of the "unnie" was I Do, I Do (I loved Kim Sun-a in My Lovely Sam Soon) but in this case I definitely did not stay for the story...

It's a hard and kinda weird question.

There are a lot of dramas I started for the actors and I didn't like but still watched till the end. But the question is more about starting a drama for an actor and liking it until the end and there are a lot of them too. But being more immersed in the story than the actors, I think there was Tomorrow, the actors being just a string to connect the different stories.

Oh man so many!

1. Because this is my first life: can’t for Lee min Ki, stayed and rewatch every year due to story and everything else in this drama!
2. Be melo: came to see ahn jae hyun in a lead role and stayed for the story AND him!
3. Move to heaven and taxi driver: came for Lee hee joon and stayed for the stories and absolutely gobsmacking execution!
3. Hospital playlist: came for yoo yeon suk and jo jung suk, stayed for chae song hwa and her best friends and the stories!

That would be DP - for Jung Hae In - and Military Prosecuter Doberman for Ahn Bo Hyun, and also for pretty Jo Bo Ah kicking ass!
I don't usually gravitate toward military dramas, so I tuned in just because of the cast and I really liked both dramas. Especially D.P., one of last year's best, imo

Seo Kang joon!
I first saw him in When the Weather is Fine and while it was airing, I managed to watch Watcher (awesome Police thriller), Are you a robot too (very fluff, much fun). Oh, SKJ will be forever be credited with helping me make it through our long and strict Covid confinement...
A bit later I also watched The third charm (SKJ hanging out in my birth city! I dived in so happily not knowing I was in for a world of pain), and Cheese in the trap (the Baek siblings were the highlight of the drama). Currently I have Grid on hold because availability is hard, but I was finding it ok

That would be this years Through the darkness starring Kim Nam Gil. I love that Oppa to bits and couldn’t resist at least trying out his drama out of loyalty to him. So glad the story was just as gripping, well written and thought provoking.

I wouldn't call them oppas or unnis who make me watch some kdramas, but it's mostly the actors that roped me in, at least in the beginning of my kdrama-watching-journey. When I stumbled upon my first one, "Signal", I was intrigued by the story and didn't find anything else to watch so I gave it a try. I binged through this very fast and was blown away by - everything. Storytelling, language, culture, everything was new to me. But I wanted more! But I knew nothing at that time about kdrama, so I had to start somewhere, and that's often the actors. So after Signal I looked up Kim Hye-Su's dramas and found Hyena which I loved (and still do). Hyena introduced me to Ju Ji-Hoon, so Kingdom was next (I usually don't like zombie shows, but this one worked for me). After that I remembered Lee Je Hoon at some point and voila, "Move to Heaven". For me that's just a way of working myself through the kdrama-landscape - take your favourite actresses and actors and look up their back catalog (or future projects), then one thing will automatically lead to the next. Temporary crushes do happen along the way, though...😉 But it works the other way rpund as well. By now I've watched a number of kdramas, and sometimes Icome across an actress or actor who just doesn't work for me. So when they're in a drama I'm about to watch and I see them in the cast list I won't start it.

Life: I came for Cho Seung Woo (not Lee Dong Wook).

Suits: I came for Park Hyung Sik.

But more often, I came for an actor but the story was not appealing enough to make me stay. Examples: almost everything Park Seo Joon is in, many things Wookie is in.

Watched Prison Playbook and Life on Mars for my bias Jung Kyung Ho - and ended up falling utterly in love with the plot. ❤️❤️❤️
Heck, I could even say the same for Hospital Playlist - although for this one, it was for the 5 main leads and the writer-director combo. Still goes down as my favorite kdrama. Tbh, I still have to watch a JKH show that will disappoint me, 'coz even with One More Happy Ending and Falling for Innocence, I still look back with fondness. He really does know how to pick his projects. ^^

Oy vey, is this title heteronormative or what? Why not came for unni, oppa, our KDrama person, stayed for the story (or the cinematography, OST, humour, hanboks, pinyeos and last but not least, squeezable child actors)?

It's pretty rare that I watch because of the cast but it has happened.

Legend of the Blue Sea for Jun Ji-hyun, coming off My Love From the Star. (That in turn led to Boys Over Flowers but that wasn't about wanting to see more Lee Min-ho, just the realisation is that it's a kind of reference point for so much in dramaland).

XX for Hani/Ahn Hee-young, coming off Idol: the Coup. Definitely glad of this as otherwise I wouldn't have heard of it. A second attempt with You Raise Me Up was less successful, though I stayed to the end.

I've more commonly gone for the oppa but got driven away by the story. Case in point: at the height of my love for Cha Seung-won I started on Greatest Love. It was truly painful, especially after seeing him in films like Blood Rain and Murder Take One.

This is the point where I reprise last year's ode to Bloody Romance. I came for the utterly talented and charismatic Wang Duo and while his character was the most enchanting thing about the drama, there is nothing about the show that isn't awesomely executed.

But the actor I most commonly start dramas for if nothing else appeals is actress Bai Lu. She's just amazing.

Think about it, I don't have one. Even my fave actor if he acts in medical drama or political/law heavy drama, it doesn't temp me to watch one, especially medical themed drama. And bad drama is bad drama even it has my favorite actors and actress.

Six Flying Dragons - wanted to see more of Yoo Ah In and decided I will sit through a serious historical drama for him. Didn't expect to get so invested in the story but it was great.

Happiness - who would have thought I would enjoy a drama about zombies? Not me ever! But Park Hyung Sik reeled me in and I ended up liking this drama so much it earned a spot on my Top 10 Dramas list.

I rarely watch only for actor and end up watching for story. alot of times when I watch for actor without considering behind the scene I end up dissapointing. But always pick up all the positive side despite I'm not enjoying it. but one that rare occasion I end up love the drama might be romantic dr 2. I avoid Medical drama like plague, but I watch It for Ahn Hyo Seop bcause I start loving his performances in Business Proposal. But I end up surprisingly love the drama. and to my surprise, no wonder i love it since the PD is Yo In Shik. The second drama I end up love it is the innocent man. I watch it for Song Joong Ki and end up loving it so much despite it's flaws. I end up becoming a fan of director work afterwards. That one rare occasion, but it's rare.

Hmm, for me there are three dramas that qualify:

Park Seo Joon in Itaewon Class. I generally avoid IP dramas because of the drama of the original work's fans, but I came because of him and fell in love with the story.

Kim Soo Hyun in The Producers. I had just finished My Love From Another Star some months before and wanted to watch some other works he was in. This is the drama that introduced me to IU 😁

Le Je Hoon in Move to Heaven. It was truly an interesting watch.

Queen Seon Deok. I started it for Kim Nam Gil (after watching him in Live up to your name) and I stayed for everything. It's a wonderful drama.