Emotions
Emotions or feelings have always been a key point of interest in personality theories. At the lowest level, we have pain and pleasure, which are really more like sensations than feelings. There is also psychological pain and pleasure -- call them distress and delight -- which may be the root of all other emotions. Distress is what we feel when the events of the world are more than we can handle. Delight is what we feel when we discover that we can handle them after all!
Anxiety is a favorite topic in personality theories. Although many definitions have been proposed for anxiety, they tend to revolve around unnecessary or inappropriate fear. Kelly notes that it is actually the anticipation of a fearful situation, accurately or not. Fear, in turn, is usually understood as involving the perception of imminent harm, physical or psychological. These definitions serve well for most circumstances.
Guilt is another key emotion. Related to shame, it is usually understood as the feelings aroused when one contravenes internalized social rules. Kelly provides a useful elaboration: He defines it as the feeling we get when we contravene our own self-definition (which may or may not involve those standard social rules!). Existentialists add another detail by suggesting that guilt is closely related to the sense of regret, of opportunities not taken.
Sadness is the experience of the world not being as it should be, with the added notion that we have no power to alter the situation. Instead, there is a need to alter ourselves -- something we are innately reluctant to do! Grief would be the obvious extreme example, and depression could be defined as unrealistic sadness that continues long after the original situation.
Anger is similar to sadness: The world is not as it should be. But now, there's the added notion that we must energize ourselves to change the situation. When we act on our anger, it becomes aggression. Anger and aggression are not necessarily bad: It is our anger at social injustices, for example, and aggressive action to correct them, that makes for positive social change! Unrealistic anger, the kind we hang on to despite the suffering it causes us and the people around us, could be labelled hostility.
There are, of course, many other emotions and emotional shadings we could try to define, but that's for another time and place. Just one more thing should be noted: It appears that, where there is consciousness, there is emotion -- at very least an emotional tone or mood. As the existentialists point out, we just cannot not care.