I’m a ‘glass 50%’ kind of a person.
You can’t tell whether a glass is half-full or half-empty until you know whether it is being filled or being emptied. Otherwise, you are in danger of applying the wrong solution – or you may end up doing nothing when action is needed.
It’s surprising how often people describe themselves as ‘glass half-full’ kinds of people… and perhaps equally surprising that, in reality, most of us are aware that the key information is what’s happening to the glass’s contents. In 2003, some researchers showed that “speakers tended to describe a 4-ounce cup filled to the 2-ounce line as half full if it was previously empty, but described it as half empty if it was previously full” [full article here].
This is different to being optimistic or pessimistic. A pessimist looks at the glass and thinks nothing can be done to improve the situation, unlike the optimist who thinks the opposite. But an optimist who fails to see things as they really are is in danger of not acting when required – and will be disappointed when the glass is completely empty, even though appropriate action at the right time could have led to its being filled.
That’s why it’s better to be a ‘glass 50%’ person than either a ‘glass half-full’ or ‘glass half-empty’ person.