Bollywood dancing is the foundation of every great Indian film.
Songs typically comment on the action taking place in the movie, in several ways. Sometimes, a song is worked into the plot, so that a character has a reason to sing; other times, a song is an externalization of a character’s thoughts, or presages an event that has not occurred yet in the plot of the movie. In this case, the event is almost always two characters’ falling in love.
“Songs are a mode of indirect expression whereby characters can articulate thoughts and desires which may be inappropriate to state directly.”

 – Tejaswini Ganti, Bollywood: A Guidebook to Popular Hindi Cinema