A very memorable character from the Hitchhiker's Guide to the Galaxy, Marvin will always find the worst in everything or complain about how bad anything is. He could make winning the lottery seem like the worst thing that could happen to someone.
His meme's are generally in the form of "I could XXX, but you won't like it." or "Here I am, brain the size of a planet, and they ask me to XXX." No matter what is chosen, the slant is very very depressing, even when it shouldn't be (though sometimes it is).