Why does Caesar not read Artemidorus's letter in III.1 of Julius Caesar?

You could say that the Fates decreed that he not read the letter because his fate had already been determined. In the play, however, it is the way Artimedorus presents the message that makes Caesar turn him away. As Caesar arrives at the capitol, both Decius and Artimedorus approach him with petitions. Artimedorus shouts that Caesar should read his petition right that minute because it is a message that "touches Caesar nearer." However, Decius presents his message by saying that Caesar can read his "humble suit" at Caesar's "best leisure." In a move meant to show his own humility, Caesar says that any message that concerns his own good should be the last thing he considers. So he brushes Artimedorus aside.