Our sweetest songs

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.

- From To a skylark by Percy Shelley