Kdramas that started slow or bad but redeemed themselves at the end

I saw an old interview of Quentin Tarantino where he said that movies nowadays are no longer telling a story, they are telling a situation. Stories should unfold, while situations are quick.

That made me realize that was how I watch dramas nowadays. I would drop it in a heartbeat if it didn't catch my interest in 1 or 2 eps. I can't wait for story to unfold, I want it pack right at the beginning.

So please, recommend me dramas of any genre where it started slow, boring, bad, but you found it good and even great toward the end.

TIA.