CBT - Cognitive Behavioral Therapy

Is the glass half empty or half full? is a common expression, used rhetorically to indicate that a particular situation could be a cause for optimism (half full) or pessimism (half empty); or as a general litmus test to simply determine if an individual is an optimist or a pessimist. The purpose of the question is to demonstrate that the situation may be seen in different ways depending on one's point of view and that there may be opportunity in the situation as well as trouble.

This idiom is used to explain how people perceive on events and objects. Perception is unique to every individual and is simply one's interpretation of reality.

Cognitive behavioral therapy (or cognitive behavioral therapies or CBT) is a psychotherapeutic approach that aims to solve problems concerning dysfunctional emotions, behaviors and cognitions through a goal-oriented, systematic procedure. The title is used in diverse ways to designate behavior therapy, cognitive therapy, and to refer to therapy based upon a combination of basic behavioral and cogn...

Optimism is "an inclination to put the most favorable construction upon actions and events or to anticipate the best possible outcome".

It is the philosophical opposite of pessimism. Optimists generally believe that people and events are inherently good, so that most situations work out in the end for the best.

Alternatively, some optimists believe that regardless of the external world or situation, one should choose to feel good about it and make the most of it. This kind of optimism doesn't say anything about the quality of the external world; it's an internal optimism about one's own feelings.

A common conundrum illustrates optimism-versus-pessimism with the question, does one regard a given glass of water, filled to half its capacity, as half full or as half empty? Conventional wisdom expects optimists to reply, "Half full," and pessimists to respond, "Half empty" (assuming that "full" is considered good, and "empty", bad).