I have felt an instant connection with a numebr of people “at first sight” – with no prior interactions – and turned out to have things in common with them. I think that we sometimes recognize things in other people’s appearance that give us a sense of comfort or familiarity; or – as @LezboPirate says, a sense of distrust or aversion.
The one time I experienced an instant romantic connection with someone, it wasn’t a head-over-heels lust; rather, it was a feeling that I had known him for my whole lifetime within the millisecond that our eyes first met. Unfortunately, the context was a support group for kids whose parents were divorcing… so being the first relationship either of us had soon after our marriages ended, it was destined to fail. Under different circumstances, I feel that he and I were very compatible and might have had a strong relationship.
All’s well that ends well… I ran into him a couple years later and he had a ring on his finger. It took me a while longer, but I now have a ring on my finger, too. My fiancé and I met on a social forum (not a dating site) and struck up a friendship. We met as friends a few times and the compatibility was strong, and it didn’t take long before we decided to become a couple.
@uberbatman: Congratulations!