Ideal Association (5-9 Sun Sign Pattern): Gemini and Aquarius
Not always, but surprisingly often, the extraordinary magnetism of 5-9 Sun sign attraction leads to easy sympathy, mental stimulation, emotional affinity, romantic fulfillment. There will be a strong sympathy between you and misunderstandings will not be severe or lasting. The chances for harmony are excellent, and a happy relationship on a permanent basis is more effortlessly achieved than with any other sign - be it friendship, business, family or love relationships. Hostile placement of planets between the two horoscopes will cause some personality clashes and tensions - causing the compatibility to rock from time to time - although the basic empathy and understanding will always remain. If the planets are in harmonious aspect, your relationships with these people will be most extraordinarily happy, smooth and sympathetic.
I definitely agree with this. I've always been close to Libras and Geminis
I've heard its because the 5-9 pattern means you know each other from past lives :O