Saturday Night Fever
John Travolta ran two miles a day and danced for three hours a day for nine months to prepare for this role. He wanted to prove he wasn't just a TV sitcom actor (he was famous for Welcome Back, Kotter at the time). The "You Should Be Dancing" solo was his chance to show pure physical dominance. The scene is crucial because of the context. Tony Manero (Travolta) lives a bleak, gritty life in Brooklyn. The discotheque is the only place where he has status. The choreography captures that arrogance and intensity. He isn't dancing to have fun; he is dancing to demand respect. The famous white suit that Travolta wears in the poster (and the dance contest later in the film) was originally supposed to be black, but the costume designer changed it so he wouldn't blend into the dark nightclub background. This film single-handedly popularized disco globally, extending the genre's lifespan by several years. The floor he dances on was a custom-built "Infinity Floor" that cost $15,000 to build in 1977, lighting up to the beat of the music.