From Charlie Brown Comic Strip

Snoopy is dancing up a storm.
A big smile on his face.
He’s as happy as can be.
Lucy comes along.
She says “You may be happy today,
Doesn’t mean you’ll be happy tomorrow.”
Snoopy ignores her.
He just goes on dancing.
She keeps looking at him unapprovingly,
And then says,
“Happiness isn’t everything, you know,
It will never bring you peace of mind.”