Absence makes the heart grow fonder.

一日不见，如隔三秋

A separation enhances love.

This counterpart of FAMILIARITY BREEDS CONTEMPT first appeared in an anthology of poems published in 1602 (it was the first line of an anonymous poem), but it was more or less ignored until it reappeared in 1850 as the last line of a song, "The Isle of Bearty," by T. Haynes Bayly. Within the next half-century it was used so much that by 1900 it was a threadbare cliche.