Regret is about not knowing then what we ended up knowing later. So, when faced with a day of appointments that are hard to cancel, I can look ahead and say to myself: If you don't go now and something goes awry, you will regret it later.
Most of my clients this week had a theme of being stuck in regret. And I laughed to myself because I was actually in the middle of doing the same round of work on myself that I was asking them to do. Since I was so raw in this area, I was even more able to help than usual.