Secondly, the scene can be used to develop the character of the Nurse. By showing her to be a warm, funny and caring individual, Shakespeare helps us to understand her relationship with Juliet and why Juliet trusts her so much. This makes the Nurse's death in Act V all the more tragic.
Thirdly, the scene can be seen as a commentary on the social and political climate of the time. The Nurse's often bawdy and earthy language can be seen as a reflection of the lower-class culture in which she lives. This can be contrasted with the more refined and poetic language used by the upper-class characters, such as Romeo and Juliet.
Finally, the scene can be seen as a way for Shakespeare to explore the theme of love. The Nurse's coarse language and behaviour can be seen as a contrast to the more romantic and idealised love between Romeo and Juliet. This can lead us to question what is 'true love' and what are the different ways that love can be expressed.
In conclusion, there are many reasons why Shakespeare might have included the humorous scene with the Nurse in Romeo and Juliet. It provides light relief, develops character, comments on society and explores the theme of love. All of these elements contribute to making the play a rich and complex work of art.