One thing I was think about is the rather internalized misogynistic notion that women are always in competition with each other...usually over a man or dating prospects. Thus if the bland, blank-slate waif virginal protag has a super modern, cool, stylish "best friend", it will be seen as more of some kind of gross victory when the super hot, dashing, tall dark and kinky rich hunk chooses the 'self-insert' protag over the stylish best friend.
Which is gross. Who cares.
Thus why I avoid a lot of romance novels and movies. I write my own dark twisted shit.