A pessimist in denial. Someone with an overwhelmingly negative view of the world and the future, but does not want the stigma associated with being called a pessimist, so they claim to view the world as it "really" is. Of course, in the eyes of the realist, it's never "really" good, it always "really" sucks.
Person A: You know, I hate people, the future sucks, life sucks and then you die. Might as well off myself right now.
Person B: Wow, you're a real pessimist!
Person A: I'm not a pessimist, I'm a realist.