We look before and after,
And pine for what is not-
Our sincerest laughter
With some pain is fraught-
Our sweetest songs are those that tell of saddest thought.

Yet if we could scorn
Hate and pride and fear;
If we were things born
Not to shed a tear,
I know not how thy joy we ever should come near.

-Shelley, from To a Sky-Lark