Mood also differs from temperament or personality traits which are even longer lasting. Nevertheless, personality traits such as optimism and neuroticism predispose certain types of moods. Long term disturbances of mood such as depression and bipolar disorder are considered mood disorders. Mood is an internal, subjective state, but it often can be inferred from posture and other behaviors."
I agree it can be useful to define what a mood is and yet since the '1st Forgotten Fundamental of Life' is "The individual Is The Meaning Maker", each person will have a meaning for the label 'mood' that works for them. Having a meaning for moods does not give one the knowledge to control changing moods.
If you want to manage changing moods, a valuable and practical suggestion is to come to a personal understanding of the structure of how a mood is created (however one defines a mood). It's like knowing, how to build a building then you can use the tools you have to build, re-build, construct, and demolish any building on the planet. It works the same way with moods, emotions, beliefs, etc. Once one knows the structure of how it is created, one can play with the structure and dis-create, change or shift any mood, belief, emotional response in time or through time. Now you have the power of changing moods at your command.
I've noticed that for me; how I feel as I am waking in the morning (what thoughts are tumbling through my mind) determine the overall mood for the day. I can also feel if the "mood" is going to be less than useful and I begin removing the charge that is attached to the meaning of the thoughts and the direction they are going in my mind.
Sometimes, I'm not sure if it is the amount of sleep so much as the part of the circadian rhythm I am waking up in (going up or coming down) that brings the tiredness that contributes to a mood of irritability. I do know when I address my charge around tiredness and/or irritability it moves me to a place of inclusion where I can actual choose the mood I want to be in. I've noticed that using one's awareness first thing in the morning to set the tone or mood for the day makes it fairly easy to move into that mood even when something occasionally happens that could move one out of a chosen mood.
Moods are made of energy and when it comes to everything being energy, for humans the expression of energy is in the power of thoughts, as thoughts determine feelings and a mood is a feeling. A cluster of thoughts going in either direction (+/-) are power thoughts. That is why it is valuable to train your thinking.
You can learn more about what causes moods, what are moods and dealing with changing moods by getting your complimentary copy of Dr. Houston Vetter's new book, Train Your Thinking, The Power Portal For Long-Lasting Success" by clicking here TrainYourThinking.com