I personally think it's Oh My Ghost. It's my favorite drama ever. Every single episode is so fun to watch, I really enjoy watching it.
And also The Moon Embracing The Sun.
I have never felt the same way with other dramas.
-Signalㅠㅠ
-Stove League, Stranger 1
-Life on Mars, Moon Lovers: Scarlet Heart Ryeo
-Mr. Sunshine
-Kill Me Heal Me, Our Beloved Summer
-When The Camellia Blooms, Our Beloved Summer
-Six Flying Dragons
-My Mister
-Signal, Find Me in Your Memory
-I Can Hear Your Voice
-Goblin, Stranger, Signal
-Find Me in Your Memory
-Stove League, Stranger, Signal, Life on Mars
-It's Okay It's Love
-My Mister, Law School, Signal, My Love From The Stars, The Moon Embracing The Sun