If the opportunist is so hard-up that he needs to steal a glass of water, then he can have it.
The government would say that the glass is fuller than if the opposition party were in power.
The opposition would say that it is irrelevant because the present administration has changed the way such volume statistics are collected.
The philosopher would say that, if the glass was in the forest and no one was there to see it, would it be half anything?
The economist would say that, in real terms, the glass is 25% fuller than at the same time last year.
The banker would say that the glass has just under 50% of its net worth in liquid assets.
The psychiatrist would ask, "What did your mother say about the glass?"
The engineer would say the glass is twice as big as it needs to be.
The software engineer would say that they had intended to put more water in the glass, but cuts were necessary to make the ship date.
The physicist would say that the volume of this cylinder is divided into two equal parts; one a colorless, odorless liquid, the other a colorless, odorless gas. Thus the cylinder is neither full nor empty. Rather, each half of the cylinder is full, one with a gas, one with a liquid.
The seasoned drinker would say that the glass doesn''t have enough ice in it.