First and foremost, I think Korean art is realized by its love for naturalness. In everything from architecture to everyday furniture and ornaments to paintings, this aspect of Korean aesthetism is shown. If you look at the furniture pieces made of wood from the Koryo and Chosun period, you can see that most of the furniture, except for some of the luxurious ones used in court, have their natural wooden texture to it, unlike the furniture or ornaments of China or Japan. Chinese and Japanese people tried to artificially decorate their ornaments whereas Korean people left it at their most natural state and appreciated it that way. This aspect is also seen in paintings, too. Landscape painters like An Kyun, Jung Sun and Kim Hong Do tried to show the natural state of Korean landscapes rather than idealizing it or copying landscapes of Chinese painters. You can see the distinct characteristices of Korean landscapes, especially in the paintings of Jung Sun. Architecture also follows the natural lines of the mountains surrounding it, and is built around its natural environment rather than abolishing hills to make a perfectly ideal structure of architecture. All this appreciation for nature comes from the basic philosophy of Koreans taking to their natural peaceful environment, as is said by the late Professor Kim Wonyong. This is why when we see Korean art, we feel the overwhelming grandness yet familiarity and comfort of nature. This is also why it feels so ordinary, rather than initially decorated.
However, Korean art is much more than its naturalness. Along with this comfortable feeling, Korean art sometimes has a powerful splendour to it, shown mostly in court art. The use of primary colors in luxurious patterns is another face of Korean art that shows that Koreans also loved decorativeness in their art, which in some senses is contrary to the naturalness. Court paintings surrounding the king or furniture used by the royalty were full of brilliant floral designs and idealistic animals. Costumes for special occasions were full of colors and patterns in such detail that it would sometimes be difficult to absorb it all in one sight.
These two aspects combined together, Korean art is about being a whole. It is not just looking at one side of a picture. Although some painters like Shin Yoon Bok and Kim Hong Do showed common everyday life images and An Kyun on the other hand showed the dream world, along with the overpowering nature, Korean art as a whole is both sides together. One cannot describe Korean art by showing only one of these aspects. This is why Professor Kims opinion in Korean art being ordinary and possessing an inexhaustible flavour and depth cannot better explain its characteristics.
This sense of wholeness is in other words about humanity. Like the everyday natural lives of the common Koreans, shown in genre paintings by Shin Yoon Bok or Kim Hong Do, it is comfortableand humane. It shows how people go on living, even giving a peek of what lurks in the minds of people in their natural state of instinct, the most common example being voyeurism. Yet it has an idealism to it that shows the dreams of these people and their aspirations. It shows through great landscapes that nature is a scale beyond the human power and through detailed decorations that Korean people are also artistic in every way imaginable.
Although all art is artificial to some point, it being something that has gone through the conscience of the human mind, Korean art can be described as the closest to the human lives itself. The naturalism stated by Professor Kim comes from this philosophy of humanism behind everything. Korean art, as a whole, is really art about human beings, the Korean people themselves.