That's for me to be happy today.
Sometimes it's a choice.
Chances are the people around me will also feel happier, so, a little more happiness!
I'm not being flippant here. If you are having a hard time just now perhaps you might be able to find something that makes you happy for just a little while. For that little while you are adding to the sum total of happiness in the world, in your world. No mean achievement....
This film about a child's eye view of the Matisse exhibition will make you happy for at least one minute and fifty four seconds.