In Iaido and many Japanese martial arts, there is a concept known as Zanshin (残心). It describes the mindset at the end of a strike/attack, one remains watchful of the fallen opponent, until a point of absolute certainty that the opponent is permanently incapacitated. Only then should one begin to stand down. It is not difficult to draw parallel with our lives in terms of work, or other matters. We must ask ourselves at the end of a task, is it REALLY finished? Will something come up and bite me in the back the second I turn around? I honestly can't say I practice this in my daily life, but I am sure it can help minimise possible regrets.