"Don't let yesterday take up too much of today." -- Will Rogers, humorist
It's really easy to dwell on the past. We've all done it - after a particularly difficult day, we all sit there thinking about what we should have said or should have done. Here's the thing - while you're thinking about that, you could be making sales today!
Each day is a clean start, so make the most of it! Put yesterday behind you and focus all your energy on what you can control today.