I've been on a real journey lately. You see the person across the room and you know them... and you know they know you... but you know that they aren't going to come over and say hi... do it. Take the plunge. However the approach needs to happen, make contact. Don't wait until you see them at the next networking event and say "hey were you at the taco place the other day?" It's surprisingly empowering and frankly kind of an impressive social maneuver. The reward is giddy and powerful and immediate. It makes me feel like I've broken out of the matrix.