Sadness from romanticism (yesterday) to seasonal affective disorder (since hard-nose science overtook mood studies; see the charmingly eccentric weeping girl).
Art is a science of learning from self-awareness.
It's so lonely when you don't even know yourself, time runs too fast for romanticism.
Caspar David Friedrich, You can't win, survival is the goal, every sad picture has something valuable to say.
Hangdog eyes become artists out of despair by Ernst Ludwig Kirchner.
Caption of picture : an image of a particular artwork should be shown with little more information than its title, medium and dimensions. What I imagine to happen within the next decade is that there will be a profusion of romantic pictures around the internet.