I'm a nerd for learning systems that have lots of little details, lol. Over the past 3 years, I have become very familiar with Astrology and Human Design. They are pretty intertwined but can be used to address different things
Astrology is essentially a system that works like the stock market. It's a study that observes patterns over time. With enough time and data, patterns become apparent that allow one to "predict" future behavior, much like patterns in consumer behavior influence the stock market.
Human Design is similar. While Astrology is helpful in understanding how we communicate, relate to others, experience and process our emotions, and how we accomplish goals and tasks, Human Design shows you how you best make decisions, learn, and even what type of work is best for you.
I used to think these types of things were silly and not based on anything reliable, but in learning about them, I see how the information can be applied practically to help us understand ourselves clearly as well as identify and achieve goals that suit our lives and personalities!