When we ask “what is an emotion” we find that, as in many things, William James was a forerunner for us. Here is a summary of his 1884 essay with that title:
In PCT, "bad" emotions are mainly symptoms of
internal conflict; they result from mustering physiological resources (to do
something like kill an opponent) that are never used because another system
(controlling for non-violence) prevents it; the unused physiological
preparation is experienced as an emotion (like "anger"). "Good" emotions are
symptoms of the sudden (and possibly temporary) solution of a conflict.
Emotions are important to people as evidence of the existence of or solution
to problems; in PCT, emotions are another aspect of controlling.
No real disagreement. However, "bad" emotions seem most often
associated with loss of control whether or not internal conflict
is present, e.g., loosing control of a car on a slippery road or
seeing brake lights on a car you are following a little too
closely....