(I'm a year late in writing this review but, I had to do it. So bear with me)
It's Okay To Not Be Okay is a drama that will stick with you for a long time even after you've finished watching it. Sure it's not our typical boy meets girl, fall in love, etc. kinda story. It is more than that, and there lies its beauty. It involves themes we often don't come across in many dramas and mainly focuses on the development of the main characters. They are people that have been through hell. (So much that we wish nobody goes through.) But that's what makes them what they are. The best part? They're all in it together as a team.
A very special shout-out to my most favorite character, Sang Tae, played by Oh Jung Se- he was outstanding. Kim Soo Hyun was wonderful as always and nailed his role. The only other drama I watched of Seo Ye Ji was Hwarang but, I don't remember her so well from it. Here, I can't think of a better actress to play Ko Mun Young. She slayed it. The way she brought out the many shades in her character was impressive. The rest were just as great.
My most favorite part of the drama was the stories written by Mun Young. They may come off as just normal fairy tales but the morals behind each of them were so touching and, they were in some way related to the characters.
It's Okay To Not Be Okay is one of its kind but, there is a teeny tiny possibility that not everyone will appreciate it because it is not a light-hearted drama that everybody can enjoy. But that shouldn't stop you from exploring it. If you're hesitating to watch it, go for it. I'm sure you'll be hooked in no time.

P.S. - Initially, I started watching this drama when it was airing but got invested in another that I failed to keep up with this and eventually put it on hold for more than a year. I feel so guilty for doing that because this gem was right under my nose and, I failed to see it. (Don't be like me)

Happy Viewing! :)