how do lovers meet?

So my big question is: how do the most opposite people find themselves and fall in love? They are totally different, so aren't they suppose to disagree on everything? Perhaps there are similar qualities here and there, but why do all the long lasting marriages include the most opposite love birds?
"Her first impression of me was apalling because she met me in college where I was the only person in the room who challenged the teacher's effort to change the classtime to 7:00am. I chose a class later in the day for a reason! She thought I was a crazy because she believed it was better not to disrespect the teacher and just deal with an earlier schedule. I fell in love with her because she was very pretty, hard working, and energetic... all the things I am not. As I got to know her, I realized she was extremely smart and principled and would lead a very exciting life as my wife."--anonymous
My theory is that people who usually would never think themselves with a certain man in their life in time grow to like them... then love them. Opposites attract; it is correct in chemistry and is has proven correct in life. People get bored of their own personalities and are intrigued by the opposite of themselves. Maybe it is true that when people hate each other they would never come to like one another, but there are exceptions such as the man's quote above. Lovers for years are usually exceptions to every rule...