"Contrary to what you think, I'm kind of an ass****." Contrary? 
It's certainly a choice to admit that he basically used Yejun as a science experiement. Hearing that, I don't think I'd much care how much my little brother liked the guy, I'd clock him. Gotta treat your partner right for sure, but also extend basic human decency to people in general and not just use them to satisfy curiosity.
BUT it is pretty telling how they feel about one another now, both smiling in greeting right away. 💖
It's certainly a choice to admit that he basically used Yejun as a science experiement. Hearing that, I don't think I'd much care how much my little brother liked the guy, I'd clock him. Gotta treat your partner right for sure, but also extend basic human decency to people in general and not just use them to satisfy curiosity.BUT it is pretty telling how they feel about one another now, both smiling in greeting right away. 💖