Functions Of Art
Perhaps the goal of art is to fulfil a social need of the artist and the viewer.
Expression.
Males lean towards expressing their personality. Females lean towards expressing beauty. This is intimately linked to human sexual function, as males must prove their reliability, trustworthiness, intellect, strength and general ability to help raise children, whereas females need to attract a suitable male.
Classifications of art.
Empathic Art. An artist feels something and expresses that feeling in art. The viewer sees the art and recognises this feeling in themselves. They feel sympathy for the artist, less alone and so comforted. This type of art demands intellectual and emotional understanding on behalf of the viewer and skilled expression by the artist. This is the heart of what people think of as "good art". Take, for example, van Gogh's Wheat Field With Crows, often touted as his last painting. At first a simple landscape painting, closer interpretation of the symbols and, especially, knowledge of the artist's life and, knowledge that it was (or might have been!) his last painting before his suicide, all increase the emotional impact and meaning of the artwork. Crucially it becomes a better artwork through that knowledge because we can feel more for the artist. Skill is needed to express this art well because the artist must convey his/her feelings accurately and convincingly, so a less skilled artist would always create a lower quality artwork. The converse of this type of art conveys nothing about the artist, and nothing the viewer can relate to.
Intellectual Art. An artist makes an observation, comment or expression of intellect and understanding about an external event. The viewer empathises with the event rather than the artist, and so this is less dependant on the skill of expression of the artist. Most photography fits into this category because in a photograph it is the image that a viewer must sympathise with; the only input from the creator is in choosing what to capture, although staged photography can be more self-expressive. This is why photographs don't feel like "good art". Staged photographs, like surrealist constructions by someone like Man Ray, feels more artistic than staged scenes of actors or models, which feel more artistic than real-world documentary, which feel more artistic than random CCTV footage, because each level reduces the input of the creator.
Decorative Art. This type of art expresses no meaning or feeling and says nothing about the artist. It may be purely beautiful, or purely ugly. Some skill of the artist might be conveyed, although in the most extreme form of this art, even this is absent, such as art taken by a robotic camera.
Mementos. People desire a painting of a friend or pet, and the painting serves as a memento. The interaction of having a real person create the artwork increases the emotional experience, making the memory stronger and more pleasant. A photograph would be less emotional, and therefore less pleasant than a painting made by an artist. A painting made by a close friend would make the experience yet stronger, and a painting by an intimate friend stronger still. Thus, this art of this type fulfils and personal comforting social function.