When girls have no one to impress. . . they let their guard down, to say the least.
To people who have not attended an all girls' school, these establishments may seem drama-infested and full of preppy, bubbly girls. To those people, I say, you're wrong. Attending an all girls' high school definitely prepared me for being in a sorority, what, with all the intricate hairstyling during lunch and the CONSTANT socialization with ONLY females (flashback to recruitment). I'm not kidding, I can count the number of guy friends I had on one hand. However, in some ways being surrounded with hundreds of girls I was completely comfortable with also prepared me well enough to join a fraternity, and here's how.
Uniformity. Uniforms are a blessing and a curse. A blessing in the sense that girls don't need to spend 30 minutes each morning trying to pick a cute outfit because the nuns already have one picked out for you. Just roll out of bed, put on your too-short kilt and raggedy polo and head out the door. They're a curse in the sense that they stifle one's stylistic sense because only two outfits a week are necessary. Even on out-of-uniform days, most girls wear sweat pants. Similar to fraternity men, outfit choices are limited and everyone dresses the same.
Hygiene. Let's just say when you go to a rigorous school with an hour commute, showering sometimes gets put on the backburner. You're not really trying to flirt it up or look cute in case the occasional boy walks onto campus, so messy buns and ponytails make daily appearances, and make-up isn't even a thing. Out of my 500-girl high school, maybe ten people wore make-up daily. . . and they were not commended for it. Wearing tights in the winter also means no shaving. Every girl's dream! So, if not showering daily, messy hair, no make-up and unshaven legs don't make all-girls schools sound like a fraternity, then I don't know what will.
Culture. Everyone is so open and comfortable with each other. Girls pretty much eat like 500-pound men because well, everyone's doing it! Going along with uniformity, every single girl owns and wears the sweatshirt of an all-guys high school along with boxers or shorts under her kilt. It's a given. Thus, undergarments make sitting with legs in a "lady-like" manner unheard of. It's basically the sloppiest four years of a girl's life, similar to a frat boy's four (or five) collegiate years.
Exhibiting common male behaviors. These girls have seen more girls strip than they probably should have at this point in their lives, or ever, because girl after girl changes in front of everyone before sports practice. They have dressed up like men for spirit week (see picture above), and they are sarcastic and insensitive to boy drama in college because in high school it just didn't exist. They are not afraid to speak out and being in a class full of men has no intimidation effect on them at all. If you read these qualities, you'd think this chick was in a fraternity.