Smile !!!

You catch it like the flu,
When someone smiled at me today,
I started smiling, too.
I thought about that smile
Then I realized its worth,
A single smile, just like mine
Could travel round the earth.
I passed around the corner
And someone saw my grin
When he smiled I realized
I'd passed it on to him.
So, if you feel a smile begin,
Don't leave it undetected
Let's start an epidemic quick,
And get the world infected!