Positive psychology is a growing field of psychological research that seeks to grow the empirical data on optimal human functioning and positive emotions (e.g., longitudinal happiness)

Paul Ekman was primarily responsible for identifying many of the possible emotions of the human species and how these emotions were expressed facially. He argued that emotions were universal, though culture produced varying factors on to what extent they could be expressed and what situations/ideas would evoke which emotions. He came to this conclusion by studying emotions across cultures.

Richard Lazarus's theory of appraisal, which departs from a physiological explanation for emotion, posits that emotions are a result of people's subjective experience of an event. This theory is exemplified by the old tale of many different people looking at an elephant: each of these people will focus on different aspects of this elephant, like its ears, trunk, feet, etc. Likewise, someone's emotional experience of a busy road depends on his or her interpretation. Many might fear the busy road. Others accept it and feel content. Others focus on the sun outside and feel joy.

Emotions play a major role in signaling whether or not needs are being met. For instance, if we feel sad, this could be a signal that emotional, or even physical, needs are not being met. If we feel happy, this is a sign we've done something right that has fulfilled one need or another. There are other emotions, however, that are more complex. Things like surprise can be purely reactionary and unrelated to our needs, where our body is preparing itself to ascertain more information about the event (I.E. widening of the eyes to see more, opening the mouth for more respiration).

The statement used in the example is an example of a statement that, while discussing a psychological topic, is too general in nature to accurately reflect a valid psychological principle. Also, the statement offers no proof of its assertion, and does not mention any research in support of its assertion. Even if a statement seems intuitively accurate, in order for it to be a valid statement it must be specific, and supported by evidence.

The facial-feedback hypothesis is the idea that using the muscles involved in a certain emotion will make you feel that emotion. By expressing emotions with one's face, that emotion is intensified by the feedback loop created by this process.

Type A personalities are characterized as being very competitive, goal-driven, and impatient. Additionally, Type A personalities are most likely to exhibit high levels of anger, hostility, and cynicism. While all humans will, at some point, experience lethargy, sadness, happiness, and depression these are, specifically, not characteristic of a Type A personality.

Catharsis, when being used in the context of psychoanalysis, most often refers to a release of pent up, repressed, or strong emotions. These are often negative in nature, such as sadness or anger. In Western societies, it is most often aggression, due to the fact that aggression is a socially unacceptable emotion to display in public. 

The facial feedback hypothesis states that facial expressions can actually trigger the appropriate emotion, rather than just being a reflection of that emotion. Therefore, a scenario that exemplifies that concept is that Thomas smiling (expression) made him feel happier (emotion). 

Capgras syndrome is when someone believes that a family member, friend, or pet is an imposter and can't be convinced otherwise. Capgras syndrome often occurs after a coma or head injury.

Difficulty reading facial expressions and repetitive, stereotyped movements are associated with autism, flashbacks with PTSD, and compulsive order with OCD.