The Church of the Customer blog had an excellent post on moods in the workplace.

a. What is your personal mood?
b. Does your team amplify this mood (good or bad) or do they take on their own?
c. If there is a negatively amplified mood, how do you deter it?

Kids are great examples of this. You fly off the handle for a brief moment, not realizing it at all. The next thing you know, the kids are re-enacting your example, but at a greater amplitude than you originally perceived.