Make it a rule of life never to regret and never to look back. Regret is an appalling waste of energy; you can't build on it; it's only good for wallowing in.

The speaker urges a disciplined forward-looking stance: treat “never to regret” as a practical rule rather than a comforting sentiment. Regret is framed not as moral insight but as misdirected effort—energy spent replaying the past instead of acting in the present. The image of “wallowing” suggests a self-indulgent, immobilizing sorrow that can masquerade as reflection while producing no change. The quote distinguishes between learning from experience (which can inform future choices) and regret as rumination (which cannot “build” anything). Its significance lies in recasting emotional life in terms of agency: the past is fixed, but attention and effort can be reallocated toward what can still be shaped.