Final answer:
Capulet's servant gives the party invitation list to Romeo, which allows him to attend the Capulet feast and meet Juliet, leading to the central events of Shakespeare's 'Romeo and Juliet'.
Step-by-step explanation:
In William Shakespeare's Romeo and Juliet, Capulet's servant mistakenly gives the party invitation list to Romeo and Mercutio, which is a critical mistake that leads to the fateful meeting of Romeo and Juliet. This error sets into motion a sequence of events, as Romeo, a Montague, was not supposed to be privy to the guest list of a Capulet feast. However, the servant, unable to read, seeks help to read the list, and Romeo not only reads it for him but decides to attend the party, where he encounters Juliet, thus sparking their tragic love story.