The feelings that hurt most,
the emotions that sting most,
are those that are absurd–
The longing for impossible things,
precisely because they are impossible;
nostalgia for what never was;
the desire for what could have been;
regret over not being someone else;
dissatisfaction with the world’s existence.
All these half-tones of the soul’s consciousness
create in us a painful landscape,
an eternal sunset of what we are.

- Fernando Pessoa
From The Book of Disquiet