Today Mean Girls  celebrates its 10th anniversary, as if we needed a day dedicated to one of the best movies of our lifetime (slight exaggeration). But seriously, the hilarious film has some poignant lessons on growing up female and being true to yourself, thanks in large part to writer Tina Fey . To celebrate the timelessness of Mean Girls, we're sharing our favorite lessons on womanhood inspired by the film. The quotable 2004 movie features quite a few gems about friendship, safe sex, and dating your cousin, so take a look for a good laugh!
— Additional reporting by Tara Block
Friends Don't Date Friends' Exes
"Irregardless, ex-boyfriends are just off-limits to friends. I mean, that's just like the rules of feminism."
Fat Talk Is Contagious
Karen: "God, my hips are huge!"
Gretchen: "Oh please. I hate my calves."
Regina: "At least you guys can wear halters. I've got man shoulders."
Cady: "I used to think there was just fat and skinny, but apparently there's lots of things that can be wrong on your body."
Gretchen: "My hairline is weird."
Regina: "My pores are huge."
Karen: "My nail beds suck."
Cady: "I have really bad breath in the morning."
Safe Sex Is Crucial
"At your age, you're going to have a lot of urges. You're going to want to take off your clothes and touch each other. But if you do touch each other, you will get chlamydia . . . and die."
— Coach Carr
When in Doubt, Go '90s
Regina: "Cady, do you even know who sings this?"
Cady: "Um . . . the Spice Girls?"
Regina: "I love her. She's like a martian!"
Acting Mean Is Being Mean
"I know it may look like I was being a bitch, but that's only because I was acting like a bitch."
Halloween Is Slut Acceptance Day
"Halloween  is the one night a year when girls can dress like a total slut and no other girls can say anything about it."
You Shouldn't Date Your Cousin, First or Otherwise
Karen: "You know who's looking fine tonight? Seth Mosakowski."
Gretchen: "OK, you did not just say that."
Karen: "What? He's a good kisser."
Gretchen: "He's your cousin."
Karen: "Yeah, but he's my first cousin."
Karen: "So you have your cousins, and then you have your first cousins, and then you have your second cousins."
Let Your Nerd Flag Fly
Damian: "Health, Spanish . . . you're taking 12th grade calculus?"
Cady: "Yeah, I like math."
Damian: "Ew. Why?"
Cady: "Because it's the same in every country."
Damian: "That's beautiful . . . this girl is deep."
Being Mean Solves Nothing
"Calling somebody else fat won't make you any skinnier. Calling someone stupid doesn't make you any smarter. And ruining Regina George's life definitely didn't make me any happier. All you can do in life is try to solve the problem in front of you."
Accepting Compliments Is Hard
Regina: "But you're, like, really pretty."
Cady: "Thank you."
Regina: "So you agree?"
Regina: "You think you're really pretty?"
Cady: "Oh . . . I don't know."
Some Questions Are Off-Limits
Karen: "If you're from Africa, why are you white?"
Gretchen: "Oh my God, Karen, you can't just ask people why they're white."
Big Hair Means Big Secrets
Janis: "Gretchen Wieners knows everybody's business. She knows everything about everyone."
Damian: "That's why her hair is so big. It's full of secrets."
Gretchen: "That is so fetch!"
Regina: "Gretchen, stop trying to make 'fetch' happen! It's not going to happen!"
Being Sick Is Not OK
Karen: "I can't go out. I'm sick."
Regina: "Boo, you whore!"
We All Want to Be Liked
"The weird thing about hanging out with Regina was that I could hate her, and at the same time, I still wanted her to like me."
Sometimes You Need to Express Yourself
Girl: "I wish we could all get along like we used to in middle school. I wish I could bake a cake filled with rainbows and smiles and everyone would eat and be happy . . . "
Damian: "She doesn't even go here!"
Ms. Norbury: "Do you even go to this school?"
Girl: "No, I just have a lot of feelings."
Ms. Norbury: "OK. Go home."
Silence Isn't Always Golden
"There are two kinds of evil people in this world: those who do evil stuff and those who see evil stuff being done and don't try to stop it."
High School Is a Cliquey Place
"You've got your freshmen, ROTC guys, preps, JV jocks, Asian nerds, cool Asians, varsity jocks, unfriendly black hotties, girls who eat their feelings, girls who don't eat anything, desperate wannabes, burnouts, sexually active band geeks, the greatest people you will ever meet, and the worst. Beware of Plastics."