According to the legends of the Scottish Highlanders, this is the anniversary of the fallen angels' expulsion from paradise. That's why, they said, it was so crucial for humans to be well-behaved at this time. To blindly indulge in sin and error would set up a resonance with the malevolent exiles, making oneself vulnerable to being preyed on by them.
While you and I can chuckle at this quaint superstition, it does have a grain or truth for you to meditate on. At this juncture in your yearly cycle, you tend to be more receptive to bad influences than usual. That's why you should do everything you can imagine to attract good influences and cultivate experiences that give you the feeling that this world is a paradise.