Which K-Drama has side characters that completely stole the show for you?

I was watching Strong Woman Do Bong Soon few weeks ago. The gangsters definitely stole the show for me. I loved especially the temple scenes. They are my fav side characters!

There are so many K-Dramas I skipped most of the side character parts like townspeople in Hometown Cha Cha Cha, residents in Vincenzo, weightlifting team in Weight Lifting Fairy Kim Bok Joo. But with SWDBS, I enjoyed every single second of it, including the side stories!

Do you have any fav side characters you like? Maybe even more than the main leads/story?