I'm so glad that this drama exists. And I would never know that Ji Sung is an amazing actor if I didn't watch this one. I mean he's damn cool , how did he portray all 7 personalities I don't know but he was truly Daebak! Even Park Seo-joon was cool too and I have to say the interaction between Park and Ji Sung as Oh Ri-On and Ahn Yo-na in the cafe was a chef's kiss. The plot is well-written and the OST - Auditory Hallucination - still my most fav OST. Ji Sung has a great chemistry with Hwang Jung-eum but the FL's voice is quite irritating in some scenes. Anyways, I don't wanna give any spoilers, you'll never regret if you watch the show and if you don't watch it, you have a long way to go as a K-drama fan.

Fun fact: Both Lee Seung Gi and Hyun Bin were offered the role of Cha Do-hyun (name of the ML in series), but declined. I'm glad they did. Nobody could play this role other than Ji Sung and he proved it well.