Half Full? Or Half Empty?

I'm going to put an end to all this "glass half-full/half-empty" business. Listen up...

If the glass is empty and I fill it up half-way, then it is half-full. However, if it was full and I drink half of it then it is half-empty. Got that? That's the last I want to hear on the subject.

While we're at it, "You can't have your cake and eat it"?! Well, why else would I want a cake in the first place? Unless it is a cake of soap, in which case I wouldn't want to eat that.

I might let that one go due to lack of evidence.

Thanks.