I think your life friends are the closest to soul mates. The people whose company you enjoy the most.
Love at first sight is probably lust at first sight; chemicals racing around.
But I think also that once you love someone they have to do some pretty awful things to unlove them. I have been married twice. My first husband drove me to distraction, we were just not on the same wave length intellectually speaking and even though we are friends now he still annoys me a lot of the time. But I still care/love him in a way. But my second husband is a completely different story, we seem to bat from the same base most of the time.
And on this board there are people who I am drawn to, despite not knowing them, because they interest me and stimulate my mind. So I wonder what that is all about.