Themistocles, when Simonides said that he would teach him mnemonics, or the art of improving one’s memory, replied that he would rather learn the art of forgetfulness:

Memory, and thou, Forgetfulness, all hail!
Each in her province greatly may avail.
Memory, of all things good remind us still:
Forgetfulness, obliterate all that’s ill.

This was written by Macedonius of Thessalonica (c.500 – 560 AD), which was included in Greek Anthology. Charles Neaves wrote the English translation.

Macedonius also provided a counterpoint:

Memory, and thou, Forgetfulness, not yet
Your powers in happy harmony I find;
One oft recalls what I would fain forget,
And one blots out what I would bear in mind.