Shhhhhh! I'm smiling! ;)

You wanna know how to make me smile
Take control, own me just for the night
And if I share my secret
You're gonna have to keep it
Nobody else can see this

--
* Moves Like Jagger by Maroon 5 feat. Christina Aguilera

One of my favorites by Semisonic

Nobody knows it but you've got a secret smile
And you use it only for me
Nobody knows it but you've got a secret smile
And you use it only for me
...

When you are flyin' around and around the world
And I'm lyin' alonely
I know there's somethin' sacred and free reserved
And received by me only*

* Secret Smile by Semisonic