Constant whining or negative comments, statements and attitude. Regardless of how great something is this person will always find a way to crap negative all over it. Being around them or reading their comments for too long makes you want to kick kittens. You find them especially on Facebook or other forms of social networking.
(as might be posted on social media sites)
"I should be happy that I just won the mega lotto, but I have to pay a butt load of taxes on the money and will probably die before I can spend it. FML.. sorry to be crapping negative.. I just hate my life."