Unofficially, without me knowing because it was airing on Tv, and I was too young, it's Boys Over Flowers.

Officially, It's the K2 

Opened the doors to this world with - Suspicious Partner

Boys Over Flowers in 2009

W : Two Worlds

I was new to manhwa's and  reading Noblesse & TOG . When I caught upto translation when I saw W : Two Worlds  Trailer in which MC comes from manhwa world and it drew me in.

Autumn in my Heart 

Temptation of Wife (2008) watched it with my family, it's the most popular kdrama at that time. 

The OST of this drama is legendary!!!

i started the red sleeve but never finished it. but my first was I think she was pretty (also didn't finish) the first one I finished was love in the moonlight in 2022

Entered K-drama world with: Winter Sonata (2002) - Watched in 2012.

I *think* it would have been either The Empress Ki or Moon Embracing the Sun on Netflix but I can't remember which I watched first (I doubt I'm the only one to start watching c- or k-dramas during lockdown. After watching a few c-dramas I began to get a taste for historical/ political ones and thoroughly enjoyed both these titles).

Should try Pachinko

I don't really remember which one either the heirs (inheritors) or oh my ghost 

fun fact i never finished either of them ?

Maybe it was The Legend Of The Blue Sea(2016)