Why do so many young women treat their boyfriends like crap?

All of the girls I know that have boyfriends treat them like scum. They're very demanding and treat their boyfriend like they're a doofus and complete idiot. Also the boyfriend usually just take the treatment. Explain to me this relationship dynamic.
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Hmm...lots of good answers here. There's 3 that I like.
Why do so many young women treat their boyfriends like crap?
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