In Part I, despite how much Chun-Woo says he does not care for Shi-Woon, every time he sees Shi-Woon in trouble, he rushes to his aid. This leads to Shi-Woon gaining undying loyalty to him.
So-Sul's crush on Shi-Woon in part one is pretty funny and cute at times.
Shi-Woon getting pissed off at Chang-Ho, for trying to mess with Sae-Hee.
It's recent, but in New Waves, Elder Kwon sitting in the helicopter next to Jinie, after a battle where she actually would have lost her life, had it not been for Shi Woon's intervention. Previously, he'd been a hardass to her for her entire life. As emergency personnel work on saving Shi Woon, Smiling Sword, and Jinie, he remembers her promising, as a child, not to ever disappoint him. It's one of her defining characteristics. Looking utterly broken, he thinks to himself that she can disappoint him as much as she wants, as long as she lives. Given he was a total Jerk Ass before Shi Woon's actions caused a Heel-Face Turn, the moment is particularly powerful.
Even earlier, when Elder Kwon goes to try and kill Shi Woon, and sees Jinie lying on the ground. He had been presented up to this point as a total bastard, who stated several times that he didn't consider Jinie a member of his family and that he didn't care what happened to her as long as he could kill Shi Woon. Just as Kwon is about to get rid of Shi Woon, he spots Jinie bleeding out on the ground, promptly panics, forgets all about what he's doing and dashes to her side to see if she's all right. The old guy's really not as cold-hearted as he wants everyone to think.
Pretty much all of Sera's interactions with Shi Woon in chapter 76, as bloody injured and teary as she was, the poorgirl.
In the hospital, we see her recalling her words to him while being delirious from bloodloss and pain and she blushes - BLUSHES. She does so again when Shi-Woon comes to visit her and repeats the embarrassing words she just remembered telling him. Her subsequent reaction of pulling the covers over her face to hide her blush really shows that for all her seemingly cold and calculated behavior, she is still a girl who is capable of blushing.
How loyal the Sun-Woo clan is to Shi-Woon. Especially Elder Jang-Il Jeong, the way he acted to Shi-Woon was like an uncle to his favorite nephew.
How Jin-le warms up to Shi-Woon. When she was being strangled by Ji-Woo, she thought she wanted to get to know him more. How she protects Shi-Woon from harm when they were hit by Yong-Hyun's car, taking all the damage Shi-Woon would have gotten.
Even though it was awkward at first, Jinni and her Grandfather having a conversation as they walk, with him admitting they should do it more often.