In mankind's never ending drive to recreate itself artificially, I suppose the inevitable outcome will be robots with less than desirable traits (hopefully murder will not be among them). Think about it, if we want our creations to have emotional characteristics like happiness, compassion and ambition, it stands to reason that they might also have depression, anxiety and anger. This robot by builder justin_m_winn has been nicknamed "Mel" because he tends to be melancholic. I don't know what his primary function is, but I hope it's useful enough to overlook his tendency to be down in the dumps.

Melancholic Robot