Catharsis Factor: Virtually anytime a villain gets their just deserts.
Complete Monster: The Cult Leader is a priest who drugged hundreds of people, leading them to go insane and go missing, including children who became insane even after his arrest. He also kills a reporter by crucifying him, and attempts to murder Johan the same way before trying to rape the child Mira.
Fan-Preferred Couple: Jae Yeol/Jay and Hyung Suk/Daniel. The fact that early on most female characters that directed their attention toward Hyung Suk/Daniel only did so for his new body's looks and that Jay does NOT judge people by their appearances and is willing to get beaten up and even face his fear of dogs for Daniel's sake only made it all the more appealing.
Fridge Brilliance: Why did Jae Yeol lose in chapter 49? He let his anger get to him. For Systema to properly work, has the practitioner to keep a clear mind and not let their emotions get to them.
Ho Yay: With so many guys in the cast, this was inevitable.
Zack was is a little bit too into Daniel when drunk, to the point of almost kissing him.
Vasco and Jace are the prime example of Heterosexual Life-Partners in the series, especially emphasized by Jace's incredible protectiveness towards the former.
Seriously, any guy who spends a long time around Vasco is likely to start admiring him, with Daniel himself being a good example.
Olly Wang's admiration of James Lee and rabid fixation over Eli Jang goes beyond platonic levels.
Olly: (seeing James steal a truck) "I'm in love!"
Jerkass Woobie: Logan Lee, Daniel's bully turned out to be one. While he was always the rough type, it was only after his girlfriend cheated on him with a handsome classmate that he finally snapped and since than had developed a massive degree of Inferiority Superiority Complex towards handsome guys, with his bullying of Daniel being just one of his outlets. It doesn't excuse his past actions, but it does make them (somewhat) more understandable.
Ji-ho counts as well, especially during the Juvenile Prison arc. Even though he brought a lot of his suffering upon himself due to his refusal to take responsibility for his actions, but a lot of the torment and inhumane treatment that resulted in his Sanity Slippage is something that no one deserves to go through.
Pretty much any bully (except perhaps the one with the bandana and who was more of a cocky conman than anything else, unlike the farmorebrutalexamples) and any of the guys and/or girls who are more interested in someone's looks than anything else.
Ji-Ho in the later chapters due to his repeated Aesop Amnesia, selfishness and taking zero responsibility for all the trouble he's caused. Readers rejoiced when he gets thrown into juvenile detention.
Ron the Death Eater: Some of the female characters get this treatment, especially Daniel's possible love interests and ESPECIALLY Zoe Park/Park Ha Neul.
, Daniel and Johan became a gold mine for this.