This drama from the very beginning evokes a feeling that I've never really encountered in anything else. It makes me think of summer, of idleness, of bad air conditioning in your apartment, of beer, of riding the bus in circles because you're bored and listless, of summer sunsets that seem to last for hours. Not to get too poetic, but this is a drama that is dripping with atmosphere.
The best word I've found to describe Long Vacation is 'liminal', which is a word that is used in anthropology to mean: "the quality of ambiguity or disorientation that occurs in the middle stage of a rite of passage, when participants no longer hold their pre-ritual status but have not yet begun the transition to the status they will hold when the rite is complete". In can also be used in a more... location-based context. 'Liminal spaces' are transitional places, or waiting places like airports, bus stops and school hallways. When you are there for extended periods of time it can feel like you are in an alternate reality.
A good description of liminal spaces and the concept of liminality in psychology and anthropology is this: "You could land [in the liminal space] for any number of reasons. Perhaps a particular event or circumstance has interrupted the life you were living and now everything is up in the air. [...] The liminal space can bring us face-to-face with our inner fears about who we are, how we show up in the world, our strengths and vulnerabilities, and our successes and disappointments. It can cause us to question the very core of our beliefs, practices, and identities".
All of this is a very long way to say that my enjoyment, nostalgia, and textual reading of Long Vacation has always been based upon this idea of liminality. In my opinion it is one of the ultimate liminal texts.

While liminal spaces can sometimes be described as eerie, creepy, or unsettling, Long Vacation imparts none of these feelings. The liminality of the show is warm but somewhat listless. The apartment where the two main characters live is cramped but homey, the building itself is bland but features a huge billboard of a beach on top of it. It doesn't really rain. The sky is blue. The city is busy but feels empty at the same time. The main characters spend time on their roof (where they're probably not really supposed to go), sitting on stone walls, walking the streets, on the highway -- there's this feeling that they're inhabiting the most banal fringes of their society.
Both Minami and Sena are great examples of people who are in transitional periods in their lives and feeling lost. Minami is a model who is slowly getting less and less work, and at the very beginning of the show she is jilted at the alter. Minami is not a married woman, but she feels out of step with younger, single people. She is caught in a liminal space. Sena is a former classical pianist who is now working teaching piano lessons to children. He no longer believes in his ability to be a great piano player, and yet he is unhappy with his life and occupation. On some level he knows what he wants, but he can't take the steps to make it happen.
Both the lead actors are excellent, bringing a charisma and vivacity to their characters. They also have such great chemistry that even their very subtle scenes (and there are a lot of those -- along with plenty of quiet, pensive gazes at one another) feel electric.
At just 11 episodes, this drama zips along very quickly, which I think makes the sluggish and hazy feeling of the show actually enjoyable rather than tiresome. We are boldly introduced to our characters and get a chance to see them in action and the show doesn't waste time with long introductions.
I don't know if it was the intention of the show creators to give Long Vacation such an intense aesthetic, but it definitely worked. In my opinion this is one of the best 'older dramas' that I could recommend to people who haven't watched very many of them. Although it is dated, it avoids many of the tropes that you find throughout older asian dramas (at least the ones I've seen). The story, characters and concept are more original and the execution is more intentional. Overall, this is one of my favourite dramas ever. It's one of the few dramas that I watched when I was younger that still hold up.