Hello :)

I'm looking for dramas or movies that feature actos, who gave their all for their role. I mean performances, that are so astonishing that it takes your breath away and you can only gaze in amazement. The dedication of the actor to his/her role should reflect.

For example I still have a huge respect for Kim Myung Min, who literally risked himself in order to make his role in Closer to Heaven more believable.

So what are dramas or movies with performances that really took your breath away? :D

Secretly, Greatly
It's Okay, That's Love
dramas:
misaeng -- all-around fantastic cast. reflecting back on the show, I'd say that lee sung min, byun yo han, & kang ha neul are my favorites in this, altho everyone is nothing but phenomenal. I especially love im shi wan as jang geu rae. he just completely embodies the role & remains the perfect choice. I'm also not much of a kang so ra fan, but she nails it here!
1 litre tears --- I wouldn't say that I was "blown away" by the acting, as I was more focused on the story & wiping tears away every five seconds. but, really, the drama would have no impact if the actors couldn't deliver, & they definitely do.
cruel city --- an intense drama that jung kyung ho slays in (& I mean that figuratively, ofc, but literally, too, I guess...)!
ishi no mayu --- I love everything about ishi no mayu, but kimura fumino is great as the rookie transfer who lacks the needed experience but grows along the way. even more impressive, imo, is aoki munetaka. even now the memory of his character is a vivid one which I credit to his acting. his character could have easily melded into the background had it been a less capable actor.
sassy go go --- this drama still makes mad! but it was worth the frustration because I discovered chae soo bin & finally witnessed how impressive ji soo is as well. both receive 10/10 from me.
six flying dragons --- I have this paused, but the talented cast is no secret here. I'm very much biased for byun yo han especially, except I was beyond impressed by the child actors to a point where I worried if the adults could match up.

drama special:

old farewell --- it would be too easy to dismiss this as ordinarily trite if it weren't for jang hyuk & jang na ra, who flawlessly deliver & allow their characters' emotions to resonate with the audience. these two are also what got me through half of fated to love you. if they ever play opposite to each other again it'd make me incredibly happy.
white christmas --- if you look at the cast then you won't be surprised why the acting impresses me. they're all known & well-liked actors now, but what really catches my attention is the year this special came out. at the time they were all fresh on scene & exhibited wonderful talent, so it's no wonder they're as popular as they are now.

movies
bleak night --- certainly not a movie to watch on whim, but the actors do such a good job. I mean, a well-written, complex script is one thing, but what good is that if actors can't convey their characters properly? with a different cast I'm sure I'd feel differently about this film, but it left me feeling stung for weeks after I watched it just as it is.
confessions --- I'm afraid anything I say might spoil even a small part of this movie but needless to say it's a well-cast movie.
a werewolf boy --- it's the moment when song joong ki finally speaks, & that's when it really hits that he hasn't said a word up til now but somehow manages to say SO much anyhow! plus, that line delivery is so <3

I'm sure I'm forgetting some but this is all from the top of my head.
I second A Werewolf Boy. That movie was magical and the acting was superb!
Soredemo Ikite Yuku is still the best acted drama I've ever watched. Given the script it requires raw and complex and intense emotion from the characters and EVERYBODY gives their bloody A++ game here, no exaggeration.
Dear My Friends has strong ensemble cast, but I was most impressed by veteran actress, Kim Hye-ja.

Han Seok-kyu and Yoon Je-moon were amazing in A Tree with Deep Roots. Their characters' face-off is probably my favorite scene in all and any Korean dramas I've ever seen.

Tang Wei really blew my mind in Lust, Caution. She played a naive, young student who pretended to be this worldly-wise woman to earn the trust of Japanese collaborator and set him up--and she successfully portrayed those two opposite characters. And the fact that it was her first feature film just makes her performance even more remarkable, IMO. And Tony Leung was great in it, as to be expected. Terrific movie, overall.
Queen Seon Deok - Go Hyun Jung (the best villain ever)
Brain - Shin Ha Kyun (I hated him, but loved him still.)
Beautiful Mind - Jang Hyuk (he portrayed a very complex character excellently. Just watch and see :)
Cheese in the Trap - Park Hae Jin (Just loved him, he's a great actor, really)
Kill Me, Heal Me - Ji Sung (it was amazing how he transforms from one character to another, I could totally distinguish who he was portraying.)
Night Flight 
Good Friends
Castaway on the Moon
Plan Man
As One
A Hard Day
Kill Me Heal Me
It's Okay, That's Love

Both very goooooooooooooooood dramas!!
I second I'ts Okay That's Love. Although you've already seen it, it might be a good suggestion for others who stumble upon this thread. Same goes for Angry Mom, I Remember You, My Love Eun Dong & The Producers who you've already completed. 

Only new thing I can recommend is Scent of a Woman.
Dramas:
Ningen Shikkaku
White Christmas
Zeni Geba
Kill Me, Heal Me
Liar Game (for Shin Sung Rok, and Lee El was wonderful here as well)
Last Friends
Seija no Koushin
Cruel City
Death Note (Kubota is amazing here, but the drama itself has its ups and downs)

Movies:
Bleak Night
Go
oh my ghost,
que sera sera
the lover
healer