Reason #1: To finally be free.
Miley Cyrus and David Crosby, they're not so different. In the '70s, Crosby sang about letting his hair grow long, and in 2012, Cyrus tweeted about cutting hers off. Length and musical ability aside, their intention was the same: to let their freak flags fly.

Short hair is to women what long hair is to men: a rejection of gender expectations and one big EFF YOU to the man, or managers, in the case of Cyrus. This past weekend after she lobbed off her famous bun (it had it's own blog, okay?) and debuted a bleached blonde asymmetrical bob, Twitter went on high alert.

"Never felt more me in my whole life," she tweeted. Then she updated her profile photo, uploaded a bunch of other snapshots, a link to an old interview where she talked about wanting Twiggy's bob, added a few more tweets for the haters including "feeling so happy in my skin[heart]" and ""[heart heart heart] LOVE my hair feel so happy, pretty, and free," and threw in a quote attributed to "Buddha."

Take that, bun-loving oppressors! At 19, the former tween sensation, who's tried everything to break from her Hannah Montana prison with bad tattoos, graphic sex talk and an engagement, finally went for the whole enchilada. The freedom cut, the thing a girl, not yet a woman, does to show the world she's her own person. For some reason, hair is that medium. Also Twitter helps, which brings me to reason #2.

Reason #2: To get attention.
If you remember when Felicity cut off all her curly hair, then you were alive in the '90s. The late-great WB series was always playing second fiddle to Dawson's Creek until sh-- got real. In a stroke of TV-writing genius, Keri Russell's character showed the world what happened when the freedom cut and curly hair intertwined. It wasn't awesome, but show ratings were.

Emma Watson experienced the power of the cut last year. "I can't believe how much of a stir this haircut caused. It's pretty nuts," she told MTV of her hair liberation. The end of her tenure as Harry Potter's Hermoine, was the beginning of a new phase in her career, and thanks to the cut, the spotlight followed her. She landed a cosmetic deal, a Vogue cover and a few darling indie roles. Really, can a short hair cut take credit for all that? Read on, friends.

Reason #3: To get respect.
Watson's cut turned her from child star into the next [insert Natalie Portman, Halle Berry, Michelle Williams or any other well-respected famous woman with short hair]. Maybe it's because short hair makes you look smarter. This is according to a Yale University study, a bright-side to other scientific findings that suggest women with short hair aren't as attractive to guys.

Who cares? Among women, facing down a pair of shears earns a kind of respect it probably shouldn't.

It's a warrior move. It says you're a free thinker, the kind of person who can go to a salon and push back against the stylist's question "Are you sure?" like Michael Jordan in an old Nike ad. "Just do it."

Reason #4: You only live once.
Every woman hankers to do it at least once in her life, usually it's just after she's come through puberty and is exhausted from overstyling in search of an identity. Enter Ani DiFranco, or bell hooks or a women's studies seminar freshman year or most likely, all three at the same time. And one day it all becomes clear. The world is divided between two kinds of people: those who want to cut their hair and those who actually cut their hair. "One day I'm gonna cut my hair like that," Miley had said. "I know I am. I will one day." Today she's living the dream.

Reason #5: To tell friends and family, 'you don't know me' (even though they probably do)
It's a gender-bending decision that usually evokes narrow-minded assumptions like "she's totally lesbianing." This is something Emma Watson said she got a lot of when she cut her hair. But if you're actually opening up about your sexuality for the first time, you don't need a haircut to prove you're brave.

Most of the time it's straight women hoping to squiggle their own line a little, or at least send the message to guys and mums: 'I don't care what you think is attractive.' It's a redefining of your own identity, and good way to attract guys who like "crazy" girls because short hair makes people think of the movie "Mad Love." To wit: "Some people just thought I'd lost my mind," Watson said of her delicate, manicured, angelically coiffed cut.

Reason #6: Because you've lost your mind
Some stereotypes exist for a reason, and in this case it's Britney Spears. In the great head-shaving meltdown of 2006, Spears was photographed buzzing like G.I. Jane. Then she attacked paparazzi with an umbrella and dodged in and out of rehab for a while. It was a tough time for the celebrity who'd spent the past decade supporting her family as America's favourite teenage sex symbol.

Asked by a photographer why she shaved her head, she answered, "Because of you." Considering the public scrutiny she was under it made sense...sort of. Another answer she gave was less convincing of sanity. She said she was "tired of everybody touching me." And later, a healthier Britney looking back on the whole debacle, asked in an MTV interview, "What the hell was I thinking?"

Reason #7: To play a girl pretending to be a guy in a movie
This is usually part of the transformation montage. Hair in the sink, ace bandage wrapped around chest, boots, cucumber in pants. You get the idea.

Reason #8: To look like Mia Farrow
From flappers to actresses who play them in movies, every generation has a short-haired style hero. Edie Sedgwick, Winona Ryder, Pat Benatar, Rihanna, Michelle Williams. "I wanted to be that girl with the short hair," writes Blogher's Rita Ahrens. "I wanted to look like Helen Slater in The Legend of Billie Jean." Her too. That girl, real or imagined, is an icon of counter-culture. An accidental beauty who's too busy running from the law, doing drugs with Andy Warhol or birthing demon babies to realize just how flattering her hair-cut really is.

Reason #9: To get over a bad breakup
It's a coping mechanism after a romantic crash, theorises Helen Fisher, a Rutgers University professor of anthropology. A drastic cut is everything from a cry for help, to a symbolic phase change. It gets you attention and distracts you from the crappy, powerless emotions you're left with after someone breaks your heart. Whatever gets you through the day.

Reason #10: To be extremely passive aggressive.
This is according to a very strange blog I stumbled on, called And they lived happily ever after. A post on a short hair serves as a (possibly misguided) warning to husbands. "If your wife comes home with a shorter hair cut one day, consider yourself warned. Talk to her. Find out what's really bothering her. Even if she claims she just wanted a new look, make absolutely sure there isn't something else bothering her."

Reason #11: To stop having your hair rule your life
"Long hair sucks ass." That's the answer an anonymous poster gave in response to the forum question, "Ladies, why did you cut your hair?" To paraphrase: long hair clogs drains and requires a lot of products. It takes forever to style, and you often have to style it leave the house, especially if it's wet and the weather is bad. Also it's hot in the summer. It gets in your eyes and your mouth. And you never know if it's doing something weird, especially when people are looking up at it and not directly in your face when you're talking to them.

Reason #12: Because you're sick.
It's the one reason that puts all the short hair vs. long hair debates in perspective. Hair, any which way you cut it, is a luxury of good health. None of it really matters.

Reason #13: To manage Olympic stress.
After narrowly missing out on a medal, Olympic hurdler Lolo Jones tweeted, "Stressed.5am no sleep post race. Almost went @britneyspears on ya & shave my head til I read ur tweets." That's fair.

Reason #14: Because you just had a kid.
"Once a baby comes along, there is rarely the opportunity for a shower much less an hour for styling and primping," writes a ParentDish blogger. "Another issue is those little hands entwining themselves into the roots. It just takes one serious pull and a fistful of missing strands to make many moms decide to schedule an appointment at the salon." Also, money, time, comfort and who cares about hair, you just had a kid!

Reason #15: To pass a drug test.
When faced with getting a hair drug test, people sometimes shave their head. This fact is based on the amount of internet questions people ask to the effect of "If I shave my head will I pass a drug test?" Sadly the answer is no, they can still test your hair follicles. But if you're really high, you might not wait for an answer.

Reason #16: Because you're Amanda Knox.
During her epic prison stint, Knox chopped off her trademark "foxy" locks. "I cut my hair 80 percent for practical reasons, so it dries quicker and I feel the heat less," she told Italy's Oggi magazine from behind bars, "and 20 percent as a gesture of rebellion to show how my situation is devastating me." Doesn't that sum it all up, though?

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