Memory of happiness

I've earned a reputation of a dude who is walking around town with this stupid grin on his face.  When I'm in the bus bus or when I'm walking around town mostly I remember a good thing that happened recently and i'm busy fantasizing over it. It feels like a small kid again. 
They say that you only know you are happy when you are not.
I kind of agree to that statement. So now everytime I'm walking with a smile, I know i'm not happy at that moment but I'm pretty much living a memory of happiness.
It kinda works for me positively. I don't have to go ranting around with my friends seeking pleasure in mediocracies ! One good incident in the first half of the day fuels me effortlessly till midnight.