Sandy's just your normal, average, everyday girl next door—if your next door neighbor is an Australian with a truly amazing set of pipes who can somehow cause cars to fly.
If you think that sounds kind of like a (warped) Disney princess, Grease agrees. Birds literally dress Sandy in the morning, according to the opening cartoon. Also, a cluster of deer, rabbits, and squirrels watch her get ready…which is actually a little creepy. But Sandy manages to be both ethereal and normcore—her biggest problems are boys and personal style, and she's hyper self-aware that these are pretty universal problems:
SANDY, singing: Guess mine is not the first heart broken; my eyes are not the first to cry […]
So how does Sandy manage to be both a Disney princess and the everygirl? Easy: Grease is a fantasy.
Even without the spontaneous musical sing-alongs, Grease isn't exactly trying to keep it real. All its actors play larger-than-life stereotypes of the 1950s. Sandy is both princess and everygirl to allow two huge populations of its audience to fulfill their fantasy.
Sandy is a princess for the girls who want to be Sandy—blonde, beautiful, wholesome, and dressed by forest animals who somehow don't poop in her hair. But Sandy is also the everygirl to be a fantasy for the guys who want to be with Sandy.
And this is exactly why cynical Rizzo—who's neither princess nor everygirl—rolls her eyes at Sandy. Her girl-next-door/Cinderella shtick is one that graced 1950s silver screens in the persona of Sandra Dee and Doris Day:
RIZZO, singing: Look at me, I'm Sandra Dee/ lousy with virginity/ won't go to bed 'til I'm legally wed/ I can't; I'm Sandra Dee!
Watch it! Hey, I'm Doris Day. / I was not brought up that way. Won't come across/ even Rock Hudson lost/ his heart to Doris Day.
Romancing the Stone
But Rizzo's scathing commentary doesn't stick, because Sandy—like Doris Day and Sandra Dee—is a romantic. She's warm and earnest, almost to a fault. Sandy wouldn't understand irony if it kangaroo-kicked her in the face. This is frustrating to Rizzo, who's fluent in sarcasm.
One great example of Sandy's honest attitude comes when she asks Marty how she can correspond with all thirty-six (our best estimate) of her different boyfriends. Marty responds by saying,
MARTY: I'm a terrific penpal. Hopelessly devoted to each and every one.
Anyone else can see that Marty is being sarcastic. She only wants her three dozen paramours to think she's devoted to them. But Sandy takes this phrase as a cue to bust out a soulful power ballad about being hopelessly devoted to Danny, a boy she spent a few days with at the beach before he turned into a total jerkface at school.
However, Sandy's honesty sets her apart. Rizzo and the Pink Ladies, and Danny and the T-Birds, both adapt their personalities to fit their peer groups. Sandy, with her inability—or unwillingness—to be biting and sarcastic, stands alone.
What else stands alone? The cheese stands alone, that's what.
And Sandy can be so darn sweet and kind that she borders on cheesy and unreal. Could Sandy's "genuine" and "wholesome" personality be a put-on persona, just like that of almost everyone else in the movie?
We're not sure. What we do know is that Sandy sheds her whole image at the end when she shows off to Danny while wearing skin-tight clothes and sky-high heels. It's up to you to decide if this is romantic—Sandy willing to compromise for Danny's interests – or upsetting—Sandy changing herself for a boy she has a crush on.
But consider this: Sandy changes her image in the most superficial way possible, by putting on a new wardrobe. It's highly likely that the real Sandy, whoever you think she may be, is the same underneath those painted-on pants.