For anyone not sure about exactly what are emotions, check out the diagram below. This diagram is based on the SASHET acronym for the 6 familes of feelings: Sad, Angry, Scared, Happy, Excited and Tender. Perhaps this is simplistic, but by using these 6 familes, we can determine what we are feeling at any one particular moment.
Here is a link to the picture you can download yourself. Make it a screen saver, put it on a t-shirt, or add it as a footer to all your emails.