“If you are wise, mingle these two elements: do not hope without despair, or despair without hope.”

A promised expectation is a polar opposite of an intrenched anguish or despondency. Is it wise to live in conflicting extremes (future and past at the same time, by example)? I don't think so. Hope is a forward looking desire of the unknown while, despair is a looking back observation of things gone wrong.

Hmm, I think what Seneca was trying to elucidate was that there is always work ahead of us and to neither take an attitude of complaisance or defeat.