Must be the winter blues.

All those dark thoughts and depressing subject matters. It must be the dead of winter. So dark and the days so short. This is not a time when you want to do overtime or stay indoors on a beautiful day.
You want to go for a long walk, or get your skates or your skis. Whatever. Get some air into your lungs and some sunshine into your brain. This world is dark enough as it is. Anything to enliven the spirit. A good dose of humor helps too. Get the paper, read the comics. And try not to look too serious while doing it.