Cubism is the one that always bugged me. But then a Cubist exhibit came to the Seattle Art Museum, so I went and looked at it. And it took you baby-steps through the process. The light clicked on for me at "Soldiers Playing Cards" by Fernand Legere. This is when I was finally able to deconstruct the image, see the scene, and see what the artist did to the scene. It blew my mind. The most fascinating painting in that exhibition to me was one I can't find any more... I believe it was Mondrian, but I am not sure now. It was round, about 4-feet in diameter, and was a white field with short black lines all over it... none of them touching... all either vertical or horizontal. He worked on that painting for 25 years. He was clearly searching for something in that image... you can see hundreds of little corrections and adjustments all over the canvas... there was a balance, or .... something that he was trying to achieve with it, and I found it riveting. If anyone has a photo of that painting, I'd love to see it...