The Optimist (and that's optimist, not Optometrist -- something that confused me when I was much younger) thinks the glass is half-full.
The Pessimist thinks the glass is half-empty.
Sir Apropos of Nothing (Tong Lashing, Peter David) wonders why there wasn't enough liquid available to fill the glass all the way up the first time.
Husband quotes an engineer joke (I don't listen close enough to have remembered the source) that it's neither half-empty or half-full, but the wrong size glass.
How many more of these are there? What's your favorite?