I very much enjoyed your article, and there's a lot of helpful suggestions. I want to offer a different interpretation of Mandino's sentence, which is that you wouldn't be focused on what you could do for someone who would be dead by midnight. You would feel a deep reverence for this person's life, knowing it was about to end. The "you may have to interact again" suggests that you're keeping in check some kind of negativity toward the other person; it's transactional and designed to facilitate future interactions, but I don't think it fosters the kind of sincerity you espouse in other tips in the article.