Letters 99.19

Tears like these fall by a forcing-out process, against our will; but different are the tears which we allow to escape when we muse in memory upon those whom we have lost. And there is in them a certain sweet sadness when we remember the sound of a pleasant voice, a genial conversation, and the busy duties of yore; at such a time the eyes are loosened, as it were, with joy. This sort of weeping we indulge; the former sort overcomes us.

Seneca, Letters to Lucilius 99.19, translated by Richard Mott Gummere