Just a Stochastic Thought

I believe you've often heard this question:
"Do you think the glass is half empty or half full?"

If you answer "half full" they'll (smugly) exclaimed "Congratulation!! Welcome to the optimist' world!!". But if you answer otherwise, they will put a pitying face and give you a long motivational and inspirational (or so they say) lectures.

Anyway, frankly, it has never made any sense to me. The first milisecond when I heard about it, well, I was rather impressed I must say, but the next second, after my brain had worked on it and sent out a signal to me, I thought "duurr... how can it be? How can a logically incorrect (or so I thought) phrase becomes part of an impressive sentence?"

OK. Let's look through it.

Let's normalize the situation. In which case, empty would become zero and full would become one. OK. Now.

Half full = 0.5 x 1 = 0.5.

Half empty = 0.5 x 0 = 0.

Half empty, in other word, is a non-existence (at least, mathematically). My hunch is, how can a realistic situation be described by a non-existence? This concept itself can't manage to find a congruence within my thinking cap.

So when a person asked me this question for the first time, honestly, I thought it was a mathematical riddle, a "trap question". Never had it crossed my mind that it is, am I correct to say it, a psychological one.

Now is the MCQ question
Do I:
a. just have a bad English?
b. just have a poor brain?
c. just have an eccentric (nyentrik) way of thinking?
d. all of the above

What say you?