15 Love Lessons for Jen... from Jen

MOVIE: The Break-Up (2006)
LESSON: BREAKING UP IS HARD TO DO—BUT WORTH IT
Analysis of the ironic lessons in this film could fill a thesis—especially because at the time of filming, Aniston was dating her costar, Vince Vaughn. Is it so implausible that Aniston followed Vaughn’s character’s initial pick-up line? “Do you think you'll marry him?” Gary asks, referring to her current boyfriend. “If you're not going to marry him, if it's not forever, then you really don't have anything to lose in [going out with me].” Way to set the bar high, Vince. Or perhaps she was empowered when she screams at Gary: “I deserve someone who gives a shit. I'm not spending one more second of this life with some inconsiderate prick… I just don't feel like you appreciate any of it... I don't feel you appreciate me.” Bonus lesson: Get even post-split by looking even sexier. Aniston’s naked strut down the hallway in The Break-Up made Vaughn eat his heart out—her semi-nude GQ cover two years later stopped a few.

MOVIE: Friends with Money (2006)
LESSON: THERE ISN’T ONLY ONE PATH
Aniston’s Olivia is the only person in her group of friends who lacks an extreme amount of disposable income. She works as a housemaid (“I'm sorry I don't have my entire life figured out”), suffers from low self-esteem, and goes out of her way to acquire free samples of moisturizer (and stealing them from her clients). Why doesn’t she have a boyfriend? “I don’t know—ask my last boyfriend,” she says. She also stalks her married ex-beau, whose wife asks why she doesn't get her own husband. “I would if I fucking could,” she responds.

MOVIE: Marley & Me (2008)
LESSON: DOGS KEEP YOU YOUNG
Aniston plays... Jennifer, a dog-loving mother of three who struggles with the demands of her marriage and motherhood. One key moment: Aniston (who cherishes her real-life pups Norman and Dolly) celebrates her husband's 40th birthday by jumping in their pool naked. “We're not old... We can still surprise ourselves," she says. Aniston, meanwhile, told Vogue, "I'm 30-10. I don't feel 40. I don't know what it means. I just know that all of a sudden it's something that's in print next to my name: And now she's 40." And now, she is.

MOVIE: He’s Just Not That Into You (2009)
LESSON: DON’T BE CLINGY
Sure, the film is stuffed to the brim with clichés and disconcerting portrayals of gender roles, but there’s something to be said for an Aniston character who earnestly explains why she hasn’t raised the issue of marriage with her boyfriend of seven years. “I haven’t wanted to seem demanding or clingy or psycho,” Beth says. “Are you ever going to marry me?…I can’t do this anymore.” So true to life that Googling “Aniston” and “clingy” returns over 23,000 results. As a source close to Aniston countered to Us Weekly last summer, “If she said she wants kids and he's not ready, that's not being needy. It's being honest.” After Aniston’s on-screen breakup with Ben Affleck’s marriage-phobic character (but before she’s called “an older model”), her sister assures her, “Tons of people make the choice to be alone.”

Happy birthday, Jen.

Henry Seltzer is a homepage editor for The Daily Beast. He previously worked at UsMagazine.com and The Huffington Post.