Van Gogh is an interesting case. He was very familiar with the art world, even before he started drawing and painting. He worked as an art dealer and traveled a lot when he was young.
Where it gets interesting is when he sets out to become an artist himself. Over the course of only ten years he produced a staggering 900 paintings. (I typically spend a few months on only one drawing. And most of those don't even have color.)
It's not that I now like his work, but I sure have learned to appreciate the man and his mission. Looking at the progression in his work and reading his letters gives a wonderful insight in the mind of a very sensitive person.