I think the dads thing at the end was supposed to be funny. As for Farm and the doctor... I don't know, I think…
I don't think he fell in love with slut doc because of that. Considering the way the character was portrayed (at least at the beginning), he was so innocent and naive that his girlfriend cheated on him "behind his back" (quite blatantly at times) and he didn't even notice. What I mean is that he seemed to be sheltered. Slut doc took advantage of this, considering his predatory behavior, and the foursome was a very evident attempt to try to "turn him" into a slut as himself. I don't think Farm is actually "in love" with him (otherwise, he would have stayed with him at the end of the prequel), but rather that he is in a very twisted co-dependent relationship with slut doc. Maybe he lacks a paternal figure and seeks that in slut doc.
On the "reversing" of the slut doc, I don't buy it, and the reason is timing. All the events of Bad Romance happen in between the end of TWM and the start of TWM:NC. The first time slut doc appears in this season is when he's on a public group video chat, possibly he's been doing shows or whatever, which implies that his behavior is the same as before. Then he has a meeting with a random guy (from his perspective) and he realizes it's Farm and he's suddenly "converted"? I don't buy it.
As you mention, and I agree, we act accordingly to ourselves, meaning that whatever others do to you doesn't necessarily dictate how you're going to act in the future. However, sometimes it does, sometimes what people do to you (or to other near you) shapes the way you act and who you become. For instance, my dad cheated on my mom, so, considering all we went through after that, for me, cheating is a deal breaker. Someone cheats on me and that's the end of it, I just cut them off out of my life (and for me that extends to all kinds of cheating/stabbing in the back/etc). What I mean with all this is Farm's behavior and rationalizing why he turned into a slut (something I hated the writers for doing that at the end of the prequel; it was completely unnecessary). Anyways, the point is that, from his perspective, he has a girlfriend that cheats on him, he then falls into the hands of slut doc, and he doesn't have a support to back on to, that would, for sure, take a toll on him. So, maybe his behavior was because of that. And now that he finds Rit and he has the opportunity to finally rebuild himself and go back to something similar as he was before, the writers do this. Doesn't seem fair for the character.
On the "support to back on to", that's something I've noticed in ALL Asian dramas, the lack of a support system for the characters. Friends and family seem to just "be there", but they rarely have an open and serious discussion about stuff, as we see in some Western dramas. For instance, at the end of the prequel, they all laugh at what Farm turned into; should't that have actually been a moment for an intervention or something? For them to have a real discussion with him to wake up and smell the coffee? Or even before, when Korn became aware that his cousin (slut doc) was playing around with Farm. Him knowing how his cousin is (it is never said but they imply that he knows how slut doc is), should't he had done something? The only character that came close to that here was Fai, but everyone just ignored her or hushed her whenever she spoke about what was going on.
Didn't really like how things developed, especially most of the ending.
Bad Romance was done first, then TWM and then this one. Continuity-wise it's a total mess, even though they tried to patch things up, but the lack of continuation on characters is what made the continuity a mess. For instance, Yihwa lives with Fai, then goes to live with the two girls, and then goes back to live with Fai. Where was Fai in BD? Where are the two girls in this one? And Cho's friend(s)? My guess is that the actors were not available, but at least mentioning the characters would patch things up a bit. Kinda like, with all this drama going on in Korn's family, his sister (from TWM) is not even mentioned (what happened to her? What happened to Phubet?).
On the storyline of this one, I think the Korn/Knock conflict was handled kinda understandably and believable, but was solved too quickly (compared to all the buildup).
The Yihwa/Cho wasn't handled well, especially because it looks like, even though she was the one who almost cheated, he seems to be the one being punished. Doesn't make sense.
And now the one that I just hated and that enraged me to the point were (when I saw how things were going) started to skip those parts: Farm, Rit and slut doc. At first, when they showed how Rit was, I though they were going to make it so Farm could go back to the sweet kid he was in the prequel and stop being the one-nigh-stand-only slut that slut doc made of him at the end of the prequel (something I didn't like, at all). That maybe he was going to make slut doc fall for him and then just leave him (which is what they hinted out was going to happen according to the events and scenes), and I even held that hope up until the basketball court scene. But the writers decided to pair him up with slut doc. Not a good ending to Farm, after all he went through.
Comparing the endings of TWM:NC and Friend Zone, it seems a bad trend is starting to emerge, one where (story-wise) things go back to zero regardless of what happens, character development is thrown to the trash and, even worse, the message that, no matter how much you're cheated on or how abusive/bad a relationship is, it's OK to be together "as long as you love each other". Plus, that the cheated-on/the victim can be treated as the bad guy of the relationship and that's OK. Bad messages.
I think the dads thing at the end was supposed to be funny. As for Farm and the doctor... I don't know, I think…
On the contrary. If you watch the prequel is the slut doc who turns Farm into this thing that's nothing compared to the kind and innocent kid he was. Rit was precisely the opportunity he had to go back to that. But the writers decided to send him to hell and live in a tortuous relationship where he's gonna be in constant fear of the slut doc going back to being a slut (which, in the real world, he would eventually).
On the "reversing" of the slut doc, I don't buy it, and the reason is timing. All the events of Bad Romance happen in between the end of TWM and the start of TWM:NC. The first time slut doc appears in this season is when he's on a public group video chat, possibly he's been doing shows or whatever, which implies that his behavior is the same as before. Then he has a meeting with a random guy (from his perspective) and he realizes it's Farm and he's suddenly "converted"? I don't buy it.
As you mention, and I agree, we act accordingly to ourselves, meaning that whatever others do to you doesn't necessarily dictate how you're going to act in the future. However, sometimes it does, sometimes what people do to you (or to other near you) shapes the way you act and who you become. For instance, my dad cheated on my mom, so, considering all we went through after that, for me, cheating is a deal breaker. Someone cheats on me and that's the end of it, I just cut them off out of my life (and for me that extends to all kinds of cheating/stabbing in the back/etc). What I mean with all this is Farm's behavior and rationalizing why he turned into a slut (something I hated the writers for doing that at the end of the prequel; it was completely unnecessary). Anyways, the point is that, from his perspective, he has a girlfriend that cheats on him, he then falls into the hands of slut doc, and he doesn't have a support to back on to, that would, for sure, take a toll on him. So, maybe his behavior was because of that. And now that he finds Rit and he has the opportunity to finally rebuild himself and go back to something similar as he was before, the writers do this. Doesn't seem fair for the character.
On the "support to back on to", that's something I've noticed in ALL Asian dramas, the lack of a support system for the characters. Friends and family seem to just "be there", but they rarely have an open and serious discussion about stuff, as we see in some Western dramas. For instance, at the end of the prequel, they all laugh at what Farm turned into; should't that have actually been a moment for an intervention or something? For them to have a real discussion with him to wake up and smell the coffee? Or even before, when Korn became aware that his cousin (slut doc) was playing around with Farm. Him knowing how his cousin is (it is never said but they imply that he knows how slut doc is), should't he had done something? The only character that came close to that here was Fai, but everyone just ignored her or hushed her whenever she spoke about what was going on.
Bad Romance was done first, then TWM and then this one. Continuity-wise it's a total mess, even though they tried to patch things up, but the lack of continuation on characters is what made the continuity a mess. For instance, Yihwa lives with Fai, then goes to live with the two girls, and then goes back to live with Fai. Where was Fai in BD? Where are the two girls in this one? And Cho's friend(s)? My guess is that the actors were not available, but at least mentioning the characters would patch things up a bit. Kinda like, with all this drama going on in Korn's family, his sister (from TWM) is not even mentioned (what happened to her? What happened to Phubet?).
On the storyline of this one, I think the Korn/Knock conflict was handled kinda understandably and believable, but was solved too quickly (compared to all the buildup).
The Yihwa/Cho wasn't handled well, especially because it looks like, even though she was the one who almost cheated, he seems to be the one being punished. Doesn't make sense.
And now the one that I just hated and that enraged me to the point were (when I saw how things were going) started to skip those parts: Farm, Rit and slut doc. At first, when they showed how Rit was, I though they were going to make it so Farm could go back to the sweet kid he was in the prequel and stop being the one-nigh-stand-only slut that slut doc made of him at the end of the prequel (something I didn't like, at all). That maybe he was going to make slut doc fall for him and then just leave him (which is what they hinted out was going to happen according to the events and scenes), and I even held that hope up until the basketball court scene. But the writers decided to pair him up with slut doc. Not a good ending to Farm, after all he went through.
Comparing the endings of TWM:NC and Friend Zone, it seems a bad trend is starting to emerge, one where (story-wise) things go back to zero regardless of what happens, character development is thrown to the trash and, even worse, the message that, no matter how much you're cheated on or how abusive/bad a relationship is, it's OK to be together "as long as you love each other". Plus, that the cheated-on/the victim can be treated as the bad guy of the relationship and that's OK. Bad messages.