I heard nothing but good things about Unintentional Love Story, so I was really looking forward to watch it and make my own opinion about it. I'm not going to lie: I was also a little bit skeptical about it for some reason, and ready to look for flaws that would make me dislike this drama at least in part.
As you might have guessed by the overall rate I chose, Unintentional Love Story ended up winning me over, and became one of the best Korean BLs I've ever watched.

The story starts off with multiple circumstances involving the main characters, Ji Wonyoung and Yoon Taejoon, that need to be kept in mind in order to make the watch more enjoyable. This is not the kind of drama that one can watch while half-asleep or unable to keep track of the plot details being revealed little by little in the story, you've been warned!
If I had to pick one recurring theme for this story, I'd say it's about freedom, in particular the need to break free from what hold people back in life. At the beginning Ji Wonyoung finds himself being swept away by situations and people much bigger and powerful than him, so he ends up acting against his own morals. At the same time, Yoon Taejoon is trapped by an intense feeling of loss and betrayal that made him unable to truly trust anyone around him. Not much is revealed in detail about these two protagonists, yet their interactions on screen and the way they slowly start taking space in each other's life and adapting to one another is a wonder for the eyes. I also really liked how they indirectly made the other people in their life change as well.
The pacing of the story was just perfect: I felt like the characters took the perfect amount of time to get to know each other and build up their chemistry, and the obstacles they found along the way were all reasonable. Even when things looked bad for their romance, I didn't feel frustrated nor annoyed at anyone's decision or train of thoughts a single time, precisely because the characterization AND the writing of the drama were so perfect - something that even dramas with the highest budget get wrong sometimes.
The two couples were very good and I really liked how different their respective dynamics were. Neither of them were a "passionate making out moments" kind of couple (if you're looking for steamy kisses and love scenes, this is not for you!), but they were both very cute. Wonyoung and Taejoon especially made a very warm and romantic couple; the secondary couple wasn't shown enough for me to make a clear opinion about it, but I've heard that a spin-off about them will be coming soon and I'm curious to see how they will do there.

In conclusion, I consider this a must-watch for any BL fan, and I also strongly recommend it to whoever wants to watch a nice romantic drama in general. Each episode lasts about 35 minutes, so it's about 6 hours overall - not too demanding at all, so dive in if you have the chance!