If I was with a girl who was "perfect" in the sense that we had the same exact interests, I'd go batshit insane. I mean, that would probably be the end of my privacy and "my thing" if she was always there to game with me, to talk about computers, listen to my music, and take interest in the movies I like. I guess I can see how the idea would be appealing at first, but annoyance would set in soon. I'm not saying that one should aim for the opposite, but take this for example.
Me and a girl went to go see Kill Bill, and she had no idea what the hell that movie was about. She also has this thing against excessive violence. Movie ends, we walk out... "Oh my God! That was horrible!" "It was fun!" "I would have never gone if I knew what it was about!" "...It's called Kill Bill. What did you expect?"
We were conversing with eachother long after. During that entire time, we were both very interested in what the other had to say. More importantly, it never degraded into mere annoyance. It was actually kind of fun. Opposites attract? Possibly. All I know is that contrast can make things very interesting.