I definitely see that as a useless question in pretty much every single way. But, for fun, I think context matters. If the glass is imaginary, who cares? If the glass is someone else's or in a neutral situation, I say it's half full. If it's my glass and, last I knew, it was full; you better believe that mother fucker is half empty. Who the hell did this?
RE: is the cup HALF FULL OR HALF EMPTY (case study: unnamed company)