Oxygen!
Wow! it really caught my attention because of the title.
I want to know why the author of the novel named it after that scientific tern. Very light series/novel.
Plus after searching the novel I also found out that it has a 2nd novel which is Nitrogen, which is also connected to the second couple of the series. Very interesting indeed.
That's why I've been watching it since episode 1.

The story was really interesting.
I want to know why and how does the oxygen may involve to the story, and I figuratively needed oxygen whenever i watch the series not just because the story itself but you will expecting more for the upcoming episodes and the production never fails to amaze me.

The cast was really great in their roles.
They play it perfectly. I've been reading the novel (english translation) and because of that I was be able to feel their characters. Supanut and Petch (Solo and Gui) was really on to their roles as well as the second couple - the Nitrogen Couple - Phuri and Boss (Phu and Kao). Yes they new in terms of acting but you can feel the emotions that they portrait.

The music is lively.
Especially the ost itself. I cannot understand thai language but you can feel the liveliness that the singer - Supanut - would want to express. I was be able to look for the english translation of the song and the music video and I was right, it was indeed very good and lively, the message of the song reflects to the series itself. looking forward for the upcoming ost of the series.

Still Rewatching...
After each episode has been played on youtube by the given day, I am still rewatching it the following day, because really, the story is cute, not that typical bl stories, it is really very light story, and even if the story was finished on air I will still going to rewatch it.

Overall...
Yes! the story/series is very lovable. For me they deserve a highest point, even though it is still ongoing because the series never fails to amaze me.