There is no worse sorrow than remembering happiness in the day of sorrow.

The sentence argues that grief is compounded by contrast: when one is in sorrow, the mind’s vivid recall of earlier happiness can become a second wound. Memory, usually imagined as a storehouse of comfort, here functions as an instrument of cruelty, because it makes loss measurable—one not only suffers now, but also re-experiences what has been taken away. The line captures a Romantic psychology in which feeling is intensified by imagination and retrospection. It also suggests why nostalgia can be painful: happiness remembered is not happiness regained, and the gap between then and now can feel more unbearable than sorrow alone.