Successful/Unsuccessful painting

Saturn Devouring His Son, by Francisco Goya from 1819–1823. I think this is a successful painting because it evokes emotions and it defiantly catches the audiences attention. Once you see it you kind of want to examine it more just to understand whats going on. 

Cowboy, by Ellsworth Kelly from 1958. I think this painting is harder to appreciate. Its not interesting or eye-catching, and it doesn't evoke any kind of emotion (at least from me). It looks really simple but for some reason it's extremely valuable.