Humans are meaning-hungry animals. We've spent centuries building intellectual edifices and metaphysical systems to try to make sense of the universe. But sometimes science, myth, religion, and philosophy don't suffice. They feel too remote, or inadequate. Besides, it's quite unlikely that any of them will tell you whether that guy was being rude or just oblivious.
Enter astrology, the belief that the positions of celestial bodies at certain key moments (like the time of one's birth) can predict or explain personality traits, historical tendencies, and world events.