How Ya Feelin'?!
The above are the classic and universal expressions associated with the basic human emotions. Many thanks for Paul Ekman and his socio-emotional-behavioral research team.
Student Shannon Cooper wrote a nice summary which I edited: Wikipedia says, "Paul Ekman is a Psychologist who has been the pioneer in the study of emotions and their relation to facial expressions. He is considered one of the 100 most eminent psychologists of the twentieth century. Ekman takes an evolutionary perspective, in that the development of human traits and states over time is the background to his research." Ekman found that facial expressions of emotion are not culturally determined but are universal to all human cultures and suggesting they are biological in origin (innate?). Ekman also discovered microexpressions which are a brief facial expression that last less than a quarter of a second. In his research called the Diogenes Project, Paul Ekman found that these tiny movements often can expose lying. Paul Ekman is also the founder of The Facial Action Coding System (FACS) which details the exact muscular-physical expressions of emotions which is useful to psychologists and animators.
So, how ya feelin'?
Much of emotion is communicated non-verbally - both it's expression and perception. Expressed emotion is 'affect', while experiencing emotion is 'mood'. Different mood states involve different patterns of activation in both physical and cognitive domains.
"Feeling" or "feelings" is another problematic term - it is probably more accurate to use sensation(s), perception(s), or emotion(s). My point is picky I suppose, but just clarify what exactly it is that you are "feeling" - it's a verb - so I am feeling angry suits me fine. Emotional processing is just another example of information processing; on the other hand, some have argued that ALL information processing IS emotional. Kenneth Dodge suggests that, "emotion is the energy that drives, organizes, amplifies and attenuates cognitive activity."
Most theories of emotion include common themes: emotion involves complex layers of processes that are in constant interaction with the environment. Emotional processing involves BOTH cognitive AND physical process.
Basic Phases of Emotion
Differential and Categorical - most simple category is the emotional valence.
Primary Emotions - more highly categorized, and yet, basic emotions such as: sadness, fear, joy, anger, disgust or surprise.
Development of emotional maturity is largely about regulating emotional responsiveness.