Oh god I don't even know where to start. The sheer excellence of this show!!!
Warning: This review WILL have spoilers coz I can't NOT spoil stuff, apparently.

First of all, the acting!! I can't believe this is Mix's acting debut, you could feel every emotion of Tian from just his expressions... brilliant, just brilliant. Earth is flawless, as usual. EarthMix's chemistry was just out of this world. The supportive cast was also so good, including the kids.
Plot wise, I think this might be the most fleshed out BL. The fact that the premise and setting itself is so different opens up new avenues for plot and character development that are rarely addressed in BLs.
For one, I think the development of Tian and Phupha's relationship was really well done. They start out with Phupha thinking Tian is some rich brat here to collect brownie points and Tian thinking Phupha is unfairly harsh on him and their view of each other slowly progresses with Tian showing responsibility and a genuine desire to be a good teacher and Phupha softening towards Tian. One thing I like is that even when Phupha is shown as being harsh, he's not outright abusive, which is a very common way to portray the so-called "hard exterior" characters. I'm not sure if it's just Earth's acting (coz he definitely has that big brother vibe that just makes everything sound sincerely caring) but even when Phupha is "harsh" to Tian, it comes off as genuine worry and care for Tian and he actually gives productive advice instead of just insulting him. (I realize that's a pretty low bar but that's where we're at with "tsundere" portrayals, unfortunately)
Tian's character is genuinely interesting. He's privileged and to some extent spoiled, but he is self-aware and it is something that digs into his conscience. Most of his young adulthood was spent traumatized by his imminent death. He also has a very obvious defense mechanism, when something threatens to overwhelm him, he puts on a facade of nonchalance, and this extends to even the possibility of his own death: he almost immediately accepts it and just asks how long he has. It also shows when Phupha confronts him on things that are very obviously eating at him, but he immediately shuts down and acts as if he isn't bothered. Though it usually dissolves fairly quickly and you can see him get visibly overwhelmed (again, kudos to Mix's acting), I think this defense mechanism is interesting to note.
I also love the character development of Tian. He starts out as someone who doesn't see himself living long enough for his life to be meaningful, and so he acts out through your typical rich brat debauchery. When his heart gives out, he doesn't expect to wake up, but he does, and this prickles at his conscience because it took someone else losing their life for him to get this "second chance" that he didn't consider himself to be deserving of. The more he learns about Torfun, the more he feels survivor's guilt as he thinks her life was much more meaningful, culminating in him realizing that he didn't just benefit from Torfun dying, the car race he started was directly responsible for it. His journey to Pha Pun Dao is one of a tormented and guilt-ridden man seeking to redeem himself by living the life of the person who saved his. At this point he's still a fairly shallow person, his trip to Pha Pun Dao is all about him feeling better about himself, and he has no plans whatsoever about how he is actually going to handle his new occupation.
He messes up several times in the early days, but he grows step by step with the help of Phupha and everyone else in the unit and the village. He forms genuine bonds with the people around him and earns their love as well. His struggle with impractical goodwill vs genuinely helpful resourcefulness is also well highlighted. The first arc ends with the fallout from his secrets about Torfun, and with its fairly neat resolution the second (shorter? not really) arc centering Tian and Phupha's relationship begins.
While I was pretty frustrated with ep 9, this conflict was actually fairly reasonable. Phupha is absolutely right in thinking that Tian might benefit from a return to his old life to re-evaluate what he wants from his life, coz Tian actually has never considered at length what he actually wants from his life - first he expected to die young and any hopes were futile, and then he was too busy fulfilling Torfun's wishes to think about his own wants. But the way he went about it, hurting Tian's feelings to "make the decision easier" for him, was a dick move. Tian is a grown adult and should be allowed to make his own decisions, it's really annoying when a character assumes they know better for a person and ends up hurting them in a major way. Tian was actually at his lowest point in this phase believing that nothing in his interactions with Phupha had come from a place of genuine care from Phupha's side. This might be my only major gripe with the plot, this was unnecessary suffering that wasn't even adequately explainable and seemed out of character for Phupha to knowingly inflict such pain on Tian - as I mentioned, he was usually an understanding and compassionate person. Honestly, when they had a genuine conversation later, I could actually agree with Phupha's side and probably Tian could too. They could've easily skipped the first half and the show would probably get a perfect score on story from me.
I also enjoyed the arc leading up to the ending, from Tian genuinely considering what he wants from his life and actively updating Phupha even if he doesn't get a response back, to the heartwarming airport scene, to him coming back two years later professionally qualified to be a teacher and still wanting to teach in Pha Pun Dao and still wanting to spend his life with Phupha. Tian was turbulent through most of the story and questioning the worth and purpose of his life, so it is only fitting that the story ends at a point when Tian has reached a clear and decisive conclusion about his life.
Random tidbits I liked about the plot:
- the fact that Torfun's wish, which is a driving point for much of the plot, turns out to be something that Tian already accomplished
- Tian and Phupha's conversations. Idk I just love them a lot. Especially the whole cliff scene the night before Tian leaves and Phupha's letter in Torfun's journal.
- the somewhat nuanced commentary on wealth, even though they don't really address it in a significant way

Minor gripes about the plot:
- the fallout over Tian's secrets was somewhat contrived and resolved too quickly. Why didn't he tell them everything in the first place? Making them believe he killed someone they loved when just two sentences more would've clarified everything seems strange. The "oh Dr. Nam suddenly rechecked the documents for kicks and discovered the timings don't match up" resolution followed by the quick shootout resolution of the Sakda plot that had been dragged out for weeks seemed a little rushed.
- the villagers' mood swings were even more abrupt and unexplained than mine when I'm on my period. To be fair hardly any series has actually fleshed out minor characters beyond a singular dimension, but this one actually raised my standards a fair bit so these things annoyed me more. The villagers hardly had any dialogues and acted like a one-dimensional monolith that switched for or against Tian at a moment's notice. Coz of this you don't really form any attachment to the villagers, unlike the kids, which made that otherwise tearjerking goodbye scene with Tian somewhat awkward: these were the same mfs giving him the stinkeye two days ago, and now suddenly he's the most loved teacher with no prior resolution?
- I understand that the series essentially centered Tian and Phupha was in a relatively stable place in life, but I wish his side of the story was fleshed out a little more beyond just falling for Tian. You don't even really see him coping with Torfun's death beyond occasional flashbacks for "oMg-ToRfUn-AnD-tIaN-aRe-So-SiMiLaR" moments. The story didn't necessarily *need* this but it would have been a good enhancement.
- I kind of hated the focus on Tian and Torfun's similarities. A lot of the times it was things Tian was blatantly repeating from Torfun's experiences and that played into Phupha's feeling of betrayal, but sometimes it was just ridiculous. Going into a "oMg-ToRfUn-AnD-tIaN-aRe-So-SiMiLaR" flashback over a fcking cabbage dish just had me facepalming. The worst was the scene when Phupha was drunk and Tian totally expected him to confess but the mf goes "yOu'Re So SiMiLaR tO tOrFuN i'M cOnSiDeRiNg ReInCaRnAtIoN". The way the smile slid off Tian's face... yikes.

Moving on, the music on this show is absolutely amazing. Every song was such a perfect fit for the scenes they were used in, and the main OST is beautiful. Definitely 10/10 material. As for rewatch value, well this review was after my first watch, but I'm already tempted to rewatch.

Overall, I initially gave this show a strong 9.5/10, with that 0.5 deducted solely coz of some small plot-related issues, but fuck it, I'm reconsidering it to a 10. It might seem weird that I said this was the best I've watched only to take digs at so many things, but the perfect show doesn't exist lol and this is definitely leagues ahead of its peers.