Second Look...

The optimist says the glass is half full. The pessimist says the glass is half empty. 
The project manager says the glass is twice as big as it needs to be. 
The realist says the glass contains half the required amount of liquid for it to overflow.

A second look at this theory may be an important step to explore the half we consider.

The cup half empty noticed what is wrong with one half. Accordingly may be ready to do something about it.

While the optimist sees the little water in, and accept it as such.

Optimist or pessimist are based on how we view things, but it's what we do about it that shape the character we would like to have. Just a thought.