they dont...
Proof as above !
It is just their nature that some will argue over anything, but it takes two to argue so think about that then !
Improved answer:
Actually, girls tend to argue alot more when they reach puberty, for example, two girls who used to be in my class when I was a kid even argued about who's bag looks better. They even argued when one of the girls touched the other! But I don't blame them, one of the girls just loved to tell lies and the other hates people who tell lies and I think one of the girls was just getting tired of the other. It is a natural habitat for girls who adore arguing like my wife used to.
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