West Side Story is a musical created in the 1950's based on Shakespeare's Romeo and Juliet. The story follows the young and innocent Maria, sister of the "Sharks" leader Benardo and Tony, who used to be a member of the "Jets". While the two gangs hate each other and often use racial stereotypes to justify their violence, Tony and Maria fall in love. Torn between his love for Maria and his dedication to his old friends in the Jets, Tony makes a horrible mistake that ruins their secret paradise.
Many people will recognize "I Feel Pretty" from a number of other movies such as "Anger Managment". The "Jets Song/dance" is often duplicated in comedies.
Despite the comedic use these songs have taken place, West Side Story was a serious love drama that brought out the horrors of racism which was prominent in the 1950's.