When I was a child and was throwing a fit, or in a yucky mood...my mom would always say "Okay Amanda, when we leave this place (store, restaraunt, etc.) you are going to leave that attitude with it.
So I would push out every ounce of the bad attitude that I could right up until I reached the last possible inch between the door and the outside. I'd stomp and huff and puff and cry. Then I'd cross over the trheshold and I'd act like everything was amazing and that I physically had left the bad mood/attitude in the last place i just was. I would come out smiling and laughing, over exaggerating how wonderful the day was.
As an adult I keep trying to take this yucky mood I'm in today and leave it in various places..but I think this may be one of the things that you lose the ability to do as you grow up.
Cause I'm trying hard...but I'm still not smiling.