Perspective? Perception?

The glass is neither half empty or half full. It is not a matter of perception, because it is both. If a glass is filled to the middle, it is both half empty and half full. What else do I have to explain here? When referencing a perspective a person has on life (optimism v. pessimism) they're referring to a stupid belief or mindset. Yes, it is blatantly stupid for the following reasons: Optimists have one perspective, the positive one, whereas pessimists contain the negative ones. However, all situations have more than one side, so why can't we utilize both to initiate an action that would end up becoming the best possible solution? A critique might be that it leads to complete indecisiveness, but I disagree. Nothing is perfectly balanced in the middle, just like the glass of water. It is either a little bit more full or a little bit less full, and by weighing the factors which are most prominent, independent of these stupid perspectives, the most productive solution can be created.