Why Courtesy?

Most of my graduate work centers around Renaissance and Classical conceptions of courtesy.  As a part of my dissertation project, which investigates the rhetorical use of courtesy in Edmund Spenser's Faerie Queene, I will be fully developing a theory of the role of courtesy in human relationships in the Renaissance period. 
I have also decided to investigate the role of courtesy in the contemporary world in conjunction with my dissertation work to add a more relevant dimension to my graduate work.  This will be a forum in which I will fully develop my personal conception of courtesy.  I welcome the input of others as I embark on this journey.