Humans have this thing where, for no reason, when ever they see males and females (or occasionally males and other males, males and squids, etc.) they have the irrational need to attempt to pair them off. Out of the blue, they have the urge to say "this person should be with this person, and this person should be with this person, and that's the way it should be".

This isn't just out of a need to create romance - Look at Fred and George! I haven't seen any fan fiction where someone tries to pair them off with other people. Why? They're already a pair. They're two units merged in such a way that they're inseparable. I'd be willing to wager that if they split ways and decided to have completely different interests, the net would suddenly be flooded with fan fiction about one or the other of them getting together with some girl.

...

Humans are weird.