I don't have children yet, but I notice that I can set the tone for the day with just my husband.  Even the dog picks up on our moods and body language, and she gets more riled up the more riled up I am and she gets worse as I respond.  

I can only imagine what this is like with more bodies in the house.  :) Here's one of my all-time favorite quotes that I try to live by - "Finish each day and be done with it. You have done what you could. Some blunders and absurdities no doubt crept in; forget them as soon as you can. Tomorrow is a new day; begin it well and serenely and with too high a spirit to be encumbered with your old nonsense." - Ralph Waldo Emerson