Bad Thinking Diary is a popular GL (Girls' Love) manhwa written by Hodan and illustrated by Rangrarii. The story focuses on the evolving relationship between two long-time best friends as they transition from a platonic bond into a romantic and physical one while navigating college life. Story Summary
The narrative centers on Kim Minji and Kang Yuna, who have been inseparable since high school. Their relationship begins to shift when Minji starts having vivid, "bad" dreams about Yuna, leading to feelings of obsession and unrequited love. As they both struggle with these new emotions, their lack of communication creates significant drama and misunderstandings. The primary conflict is driven by:
The Communication Gap: Both leads struggle to express their feelings, leading to frequent tension and poor decision-making.
Oh Hyera: The main antagonist who actively schemes to sabotage Minji and Yuna's relationship for her own amusement.
External Rivalries: Secondary characters like Cho Minjae and Han Jihoon add additional layers of jealousy and past romantic interests. Main Characters
Kim Minji: An extroverted and somewhat naive 21-year-old student whose sudden dreams about Yuna spark the series' central conflict.
Kang Yuna: Minji's introverted best friend of four years. She eventually enters a relationship with Minji but struggles with the same "bad thoughts" and jealousy.
Oh Hyera: A manipulative antagonist who introduces suspense by trying to drive a wedge between the main couple. Critical Reception
The series is widely known in the Yuri community for its high-quality art but polarizing narrative.
The manhwa industry has seen a massive surge in popularity, but few titles have captured the "toxic-yet-addictive" niche quite like Bad Thinking Diary. Written by Hodan and illustrated by Rang_Ryang, this GL (Girls' Love) webtoon has become a staple for readers who crave high-stakes emotional drama, stunning art, and the messy complications of "friends-to-lovers" dynamics.
If you’re looking for a deep dive into why this series has taken the internet by storm, here is everything you need to know about Bad Thinking Diary. The Plot: From Best Friends to "Bad Thoughts" Bad Thinking Diary
The story centers on Min-ji and Yu-na, two young women who have been inseparable best friends since childhood. They share everything, from their daily routines to their deepest secrets. However, the equilibrium of their friendship is shattered when Min-ji begins having vivid, erotic dreams about Yu-na.
These "bad thoughts" trigger a spiral of obsession, jealousy, and confusion. As Min-ji tries to navigate her burgeoning desires, she discovers that Yu-na might be harboring her own dark secrets. What follows is a psychological tug-of-war where the line between platonic affection and romantic fixation becomes dangerously blurred. Why It Stands Out
What separates Bad Thinking Diary from standard romance webtoons is its focus on the intensity of obsession. It doesn't shy away from the "ugly" parts of love:
The Art Style: The illustrations are arguably the series' biggest selling point. The character designs are sleek, and the use of color—often shifting between soft pastels and moody, dark tones—perfectly mirrors the shifting psychological states of the protagonists.
The Tension: Unlike "fluff" romances, this series thrives on tension. Every touch or glance is loaded with subtext, making the "will-they-won't-they" dynamic feel genuinely high-stakes.
Psychological Depth: The story explores how trauma and past experiences shape our "bad thoughts." It looks at how insecurity can turn a healthy friendship into something possessive. The Characters
Min-ji: Initially appearing as the more "innocent" or confused party, Min-ji’s character arc is a fascinating descent into accepting her own desires. Her internal monologues provide the "Diary" aspect of the title, letting readers see her mental struggle firsthand.
Yu-na: Enigmatic, beautiful, and often manipulative, Yu-na is the catalyst for much of the drama. Her motivations are often shrouded in mystery, keeping readers guessing about her true feelings until the very end. The Verdict: Should You Read It?
Bad Thinking Diary is a must-read for fans of GL drama and psychological romance. It is not a lighthearted story; it deals with themes of jealousy, manipulation, and the fear of losing someone by wanting "more."
If you enjoy series like What Does the Fox Say? or The Third Party, you will find the atmosphere of Bad Thinking Diary right up your alley. It is a sleek, modern exploration of how the people we love the most are often the ones who can mess with our heads the most. Bad Thinking Diary is a popular GL (Girls'
Where to Read: You can officially follow the journey of Min-ji and Yu-na on platforms like Lezhin Comics, where the high-quality English translation captures every nuance of their "bad" decisions.
"Bad Thinking Diary" seems to be a lesser-known or possibly emerging work, and without more specific details, it's challenging to provide a targeted review. However, I can offer a general approach on how to assess and review a work titled "Bad Thinking Diary," assuming it could refer to a book, manga, or another form of media.
Date: May 12
Situation: Didn’t get a reply from my friend for 6 hours.
Automatic thought: “She’s angry at me. I must have said something wrong.”
Emotion: Anxiety (8/10), shame (6/10)
Distortion: Mind reading, fortune telling, personalization
Evidence for:
Evidence against:
Reframed thought:
“It’s possible she’s busy or tired. There’s no direct evidence she’s angry. If something is wrong, she will tell me.”
Action: Send a casual check-in text tomorrow morning without apologizing preemptively.
You assume you know what others are thinking—and it is always negative. You don't ask for evidence; you just know they are judging you. Bad Thinking Diary Entry: "He didn't text back for three hours. He must hate me."
At its core, Bad Thinking Diary follows the tumultuous relationship between Yuna and the seemingly perfect heiress, Hong. On the surface, it fits the mold of a classic romance: the popular, confident partner and the quieter, more insecure love interest. However, the genius of the story lies in its namesake—the diary. No self-censorship
The protagonist doesn’t just record events; she records her worst interpretations of them. Every delayed text message, every unreadable glance, every whisper between colleagues is filtered through a lens of low self-worth. The "bad thinking" refers to the cognitive distortions we all suffer from: mind-reading (assuming we know what others think), catastrophizing (assuming the worst outcome), and disqualifying the positive (rejecting good news as a fluke).
What makes the diary so compelling is its unreliability. The reader realizes long before the protagonist does that the "evidence" she is collecting against her own happiness is fabricated by her trauma and fear.
Why would our brains voluntarily keep a diary that makes us feel terrible? The answer lies in evolutionary psychology.
Our brains are wired with a Negativity Bias. For our ancestors, forgetting the location of a saber-toothed tiger was a fatal error; forgetting the location of a delicious berry patch was just a minor inconvenience. Consequently, the human brain evolved to prioritize negative experiences over positive ones. It is a survival mechanism, but in the modern world, it is a recipe for chronic anxiety and depression.
The Bad Thinking Diary is this bias made textual. It is your brain’s attempt to "protect" you by anticipating every possible threat. However, because we no longer live on the savanna, this protection manifests as rumination, self-doubt, and imposter syndrome.
October 14th
Elena cried on my shoulder for two hours tonight. She kept saying, "Why does this happen to me?" I patted her back. I made her tea. I told her she was a victim of circumstance. Lie. The truth is on this page. I watched her cry and all I could think about was how ugly her selfishness looks when it’s wet and snotty. She is not a victim. She is a vacuum. She sucks the air out of every room until everyone is suffocating around her. I smiled so hard my jaw ached. I didn't wish for her to stop crying. I wished for her to stop breathing. Just for a second. Just to see if the silence would be as peaceful as I imagine it to be.
October 15th It’s quiet. She went out. I smiled. And this time, it wasn't fake.
You might wonder, "If I write down my bad thoughts, won't I just make them more real?" Surprisingly, research in cognitive behavioral therapy (CBT) suggests the opposite.