Mercury retrogrades throw our logistical lives out of whack and cause massive amounts of chaos. You attract members of a certain sign for a reason. Certain planetary placements warn of misfortune while others foretell of good luck. It's one thing to read these things in our weekly horoscope, but it's a whole other thing to see them come to pass in our everyday lives.
No horoscope is completely accurate 100% of the time, but every once in a while a development in our personal lives will be reflected perfectly in our 'scope, or even in our birth chart. Maybe you've been getting tired of your friend's seeming inability to make a decision, only to discover they have a Libra stellium. Or perhaps your ex has started texting you out of nowhere and a Venus retrograde just happens to be on the horizon.