Besides being the word, "Grease" is the movie defined the 1950s teen generation (though it did so belatedly -- cameras didn't start rolling until 1977) and helped cement John Travolta's film-star status.
The flick is filled with stunning choreography, some of the best sing-a-long songs in cinema history and ample amounts of teenage angst. Of course, as is the case with virtually all high-school musicals, the plot is romantically driven, only in "Grease," Danny Zuko and Sandy Olsson (John Travolta and Olivia Newton-John) have already met and fallen in love the summer before the action starts. With school back in session, Danny is so worried about losing his bad-boy image that he snubs his one true love -- to catchy tunes, of course. It's a situation many teens are familiar with, as Travolta dresses as a recluse greaser in the film, but is really just a lovesick pussycat.
When you're a teen, looking cool may sometimes seem more important than being yourself. Thankfully, it's a mindset most of us grow out of, and by the time the credits roll in "Grease," Zuko and Olsson are a public item, just as adolescents eventually learn to openly express who they are without constant fear of condemnation. We're just glad they don't all sing while doing it.