I had a friend that was so depressing that you wanted to go out and blow your brains out every time you talked to him for just a little while.
He always saw the glass half-full! With a little resin and anthrax powder mixed in the liquid.
Plus he was so sure that the person who had drunk the first half had aids.
"YOU are the one who drunk the first half of that glass of water", I told him.
"See!", he told me. "I already have aids!"