I didn't understand abstract art until I sat with the Rothko at SFMOMA for a time. The feeling came like the sound of a train - distant at first, but eventually like a heart-thumping surge of emotion. Cons: Impossible to replicate this feeling with duplicates of the original - so frequent long visits to fine art museums required.
Paintings are felt more than viewed or examined. Setting and lighting are paramount to their impact - see Four Seasons murals at Tate Modern London for his masterpiece. Cons: Staring at colors just doesn't engage some people the way it does others. His work was once called "Apocalyptic wallpaper."