I read once in a Psyche book in college that smiling actually makes you happier. 

It's something about the shape that your face takes on freeing up the blood flow through the blood vessels sending a happier, more positive feeling through your whole being!

So here's what I think...

If you're feeling down, or miserable in some way... 

Smile. 

#1 - It apparently will make you feel happier from a scientific approach.

#2 - It will make everyone around you wonder what the hell you are up to!


        - and that of course will make you happy as well... so There ya go!  Scientific fact proven!