The Love Song of J. Alfred Prufrock is all about
indecision. Suppose that Prufrock is a single, middle-aged
gentleman in the late 19th century. Now back then, when a couple had a dinner party, for example, the
man of the house would sit at the head of the table, with the lady at the foot. Now, next to the man of the house would
traditionally be seated a rather pretty young girl, to give him someone to chat and perhaps flirt with. As for the lady of the house, well, one might suppose that they would find some young hunk to sit chat with her.
No such luck - it wouldn't do at all to have some lord's wife be seduced over dinner! So to fill that spot, they usually found a single middle-aged man, perhaps someone that normally wouldn't be invited to such a party, someone "safe." It is my theory that
Prufrock is such a man, wracking himself over whether to propose marriage to some lady. His
indecision, therefore, stems from two sources: first, his
fear of rejection, and second, his unwillingness to risk being married and losing his ticket to all those parties.
Hence, he does not dare to disturb his social universe, as we find out by the end of the poem. He doesn't dare to do anything, in fact - he is paralyzed by his fear of shaking up the world around him.
Poor guy.