I have found some interpretations and thoughts on twitter and tiktok about specific scenes of the drama and wanted to put them out there;
Spoilers ahead;
---When Mi Jeong and Mr. Gu went hiking that night, it was an apparent se* scene interpretation, and that Mr. Gu never broke the lamplight, the whole hiking/kiss scene was methaphoric. The way it showed Mi Jeong showering at midnight, there was a reflection of the unbroken lamplight right there. It was quite mindblowing to the fans that realised it, especially when Mi Jeong said "I want to see heaven while I'm alive." while they were climbing up the hill, breathlessly.
---For the ending; A 500₩ coin fell. not trapped, but barely hanging. its value is small so it's "ok" if it goes down the drain. realization hits and you picked it up because despite that little value, it matters. you pick up yourself because you matter. Nothing feels more liberating than walking away from your inner demons and start wanting to help yourself.
---Mijeong was talking about how her life is divided into two parts: before and after she met Mr. Gu. We hear Mr. Gu's voice saying "Me too", that his is divided before and after Mijeong. They were together, conversing. They ended as endgame. They gave us all the closure we needed for the worship couple. Mr. Gu on his way to recovery, step by step, trudging on. And we see Mi-jeong from his beautiful point of view once more, liberated and lovable. They are together.
---The way Mijeong didn't try to change Mr. Gu until the very end. It was him who decided to recover cause no amount of alcohol can compare to having her in his life. They're going to live their lives trudging on step-by-step, once again, together.
---We also see Tae Hoon taking pictures of the rainbow recently, looking up at the sky, smiling. By the end of the drama, he came under Gi Jeong's balcony staring up at her, smiling while she was wearing the shirt with rainbow colors on it. She was most likely his rainbow.
---The drama doesn't exactly 'end'. Their journey to liberation is just about to begin. Gi jeong's new relationship with Tae Hun, Changhee's new found purpose, Mijeong finally feeling lovable and Mr. Gu abandoning his alcohol addiction. Very realistic  

I just saw the ending and it made me feel a bitter..Your post gave me closure

I love these interpretations, thanks.

Thank you for this! I'm wondering also about the bag of money he was carrying at the end and I have my own interpretation of it ..and altho idk if it's the right one, it's a happy one :)

I was so confused and wondering how to exactly interpret the ending but I was positive about the two of them and this post was on point !! Thanks 

I still think the ending was weird… not bad and not good… same consistent vibe as the entire series…. Kinda surprising… 

i still felt the entire build up went nowhere

Thank you for this post since I wasn't really sure how to interpret the ending as well. 

But after reading your interpretation, I can definitely get behind the idea that Mi Jeong and Mr. Gu are the endgame couple that will stay together. They were the couple I was most invested in and in my head as long as they stay together and help each on their liberation journey I'm satisfied

Wow, thank you for the post! Really, a lot of possible interpretations and I like that.

Omg thank you o was a little lost and I knew there was some deeper meanings I was missing! 

Thank you for that! I totally missed some of those.

For the coin at the end, I think it ties well with two metaphors Mr. Gu has said before and that were referenced multiple times throughout the drama:
 
1 - the anecdote about how survivors feel 2/3 into a fatal fall and get that "all my worries are insignificant in this moment" feeling. This could mean that he either got therapy like he suggested to his past lover, or actually attempted suicide himself but survived, or just that he got into a situation that brought him to that realization moment, 2/3 into the fall, but he was saved, just like the coin.

2 - the metaphor of how if all 7.7b humans on Earth were coins, they could be piled up to be as big as that mountain. And also how insignificant we are as little coins. This is a good indicator that the coin was indeed a metaphor for his life, and adds to the previous interpretation.

2.1 - this story about coins made me look back to the moments they were staring at the mountains, it wasn't just staring at nature but contemplating about human life, their own and how it fits in this world. I knew it had something philosophical about it but I missed the precise theme.

I recently rewatched the drama and I think I finally understood the ending. I see the coin as the metaphor of Mr. Gu’s life. It fell out of his pocket when he reached for the bottle of alcohol he just bought as if it was a sign for him. When he saw the coin lying on the edge I think he realized two things. First, how close he was to completely falling down, how close he already has been to death. But second, as the coin miraculously stopped on the edge as did his life. What a powerful sign! There still was hope for him! He still got a chance. Now, one wrong move and he might fall. But he was given a chance to change. As he picked up the coin, he left the bottle of alcohol he just bought right there on the street.

I believe the incident with Hyeon Jin (gambling addict) was what made him see how destructive addiction may be. He new he is addicted just the same and that he has to change. And the moment with the coin was a turning point. It was a moment when he made that the decision. He will start now, no more alcohol.

I see Gu at the end going to Chaiman Shin to pay off all the money Hyeon Jin stole, because in the end he was the one responsible for it. I believe he was now ready to quit that lifestyle and check into rehab. He knew Mi Jeong was there to support him no matter what and he wanted to be there for her to.

There are so many subtle moments in this drama and this moment with a coin is just a piece of the whole picture that we are left with as the show ends. I remember being confused when I finished it for the first time but now I find it very beautiful, powerful and hopeful.

I also like the 2nd interpretation from @seonni about 7.7 billion people on Earth. I didn’t think about it like that before but I believe it is very close to what producers had in mind and why they used a coin as a symbol in this scene. 

For those who are interested… it’s subbed in English. Includes some anecdotes of the screenwriter‘s perspective as well

[All Night Talk] "I'm not much of a drinker🤣" Jokester Son Sukku talks about behind stories of the

https://www.youtube.com/watch?v=k1mccn55MyA

All Night Talk] Son Sukku's thoughts about the open ending of 'My Liberation Diary' and his acting
https://www.youtube.com/watch?v=PgWt-uzQ0tI

There are another 2 episodes which you can find on YouTube, a total of 4. The ones above are the 1st and the last…

It’s really interesting how Son Suk Ku admitted that he doesn’t get the meaning behind all of his scenes… that’s how metaphoric and abstract they were. 

I appreciated how TLN allowed me to be part of their journeys. I don't judge but consider their POVs whether it is good or bad is up to them. It also made me root for them too. I loved the final snapshot because I felt the same way. I'm very glad to allow myself to feel and think about what happened in the last few episodes. Just when you get a breather to decompress... they surprise you with such unexpected moments! 

Islands in the stream
That is what we are
No one in between
How can we be wrong?
Sail away with me
To another world
And we rely on each other, ah ha
From one lover to another, ah ha

Islands in the stream
That is what we are
No one in between

I don't know if I'm right but that is how I felt at the end.