You find that you're on the same wavelength! Conversation flows; your ideas come out in a tumbling rush, and you egg each other on, urging each other for more. You agree on most things, and even the subjects you don't agree on are interesting, because you get to look at both sides of an issue together and debate over it.
At base, you think in similar ways -- your thought processes take similar tracks, ones that each of you recognize in the other. The individual styles in which each of you reasons things out and processes information blends together nicely, so you share a feeling of familiarity, almost like you're mental twins! In many ways, you are. Intellectually, you're on a par. You love discussing things together, both to hear yourself talk out an interesting subject and form your own thoughts as well as to get the other's take on it. Your love of talk and that quick mental connection also enhances your social life together. You're the couple that goes out together a lot, then goes home and talks over the entire night -- who you saw, what they said, what they wore, who they were with ... Your connection could be more mental than emotional. You should both try to dig deep in your conversations, as your inclination might be to stay on a superficial level.