If you find yourself in a "FUNK" you can probably list a few things going wrong in your life that are the "CAUSE" of your mood. It could be someone at work who just keeps pushing your buttons, a child or family member, or an unexpected car or home repair. What is it in your life that is "causing" this mood.
Now ask yourself, "if these things can cause me to be in a bad mood, who has control over my emotions?
If we allow other people and events to control our emotions, we will live in a constant state of reaction. We then GIVE away our power over our state-of-mind.
Don't confuse this with suppressing what you feel. Don't pretend to be happy when you are not. The goal is to transform the way you think and how you perceive external influences and truly take control over your state-of-mind.