Smiling is Infectious

Smiling is infectious,
You catch it like the flu,
When someone smiled at me today,
I started smiling too.

I passed around the corner
and someone saw my grin,
When he smiled I realized
I'd passed it on to him.

I thought about that smile
then I realized its worth,
A single smile, just like mine
could travel round the Earth!

So if you feel a smile begin
don't leave it undetected.
Let's start an epidemic quick,
and get the world infected!