Plots are the single most important thing in story writing. If you haven't got a good, solid plot, then it's not a story. 300 pages of introspection does not equal B-Plot. In order for something to actually *be* a story, the character *has* to want something, and must move from point A to point B. This is true for both A and B plots. Wheather the character is attempting to solve a crime, carry out a crime, get the love of their life to notice them, find out a deep, dark, secret, or get their significant other to agree to marry them, you have to have a plot and significant character motivation. A piece with 300 pages of introspection and no plot is just a vignette looking for an editor to get rid of 290 of those pages.
Laura