Overlooked aspects of character and theme
Whilst bearing the overwhelming importance of world inconsistency in mind we will now turn our attention to characters and their portrayal. A good fiction writer must be a good actor, his characters must not all be but mere extensions of his own idiosyncrasies, if so the characters will assume a kind of bland and unconvincing uniformity, becoming not separate entities, but rather, component parts of one overbearing hive mind with a totalizing consistency of thought. Characters should all have their own inner lives unless you have a reason within the story to portray them “flatly.” For example, you might wish to portray a nameless “random henchman” type character in a comedy tale to parody action genre-convention, with its seemingly endless host of utterly incompetent and drone-like shock-troopers who are curiously never daunted by the fact that their masters continuously send them up against foes girded by the indomitable power of plot-armor.
Two good examples to compare and contrast for the purposes of elucidating “well rounded” characters and “flat characters” can be found in Ayn Rand’s The Fountainhead and Atlas Shrugged respectively. In The Fountainhead all of the principal characters (and even most of the minor characters) are distinctive, both in terms of their thoughts, words and deeds whereas in Atlas Shrugged nearly all of the principal heroes are facsimiles of John Galt (with the sole exception of Dagny Taggart) and all of the principal villains are echoes of James Taggart (with the sole exception of Dr. Robert Stadler). A repetition of a certain character type is problematic because it necessitates a repetition of theme. In the case of Atlas Shrugged it is established that John Galt believes that a kind of enlightened selfishness is not only good, but the highest moral good. Since nearly all of his compatriots in the novel speak, act and think exactly like him (to the point of being indistinguishable upon the page without moniker) one knows precisely what they’re going to say and what they are going to do. Furthermore, this tendency breeds a (often unintentional) preachiness which is both extraneous and irksome; there is, after all, only so many times and ways one can repeat “selfishness is the highest good” before the reader is inclined to inwardly shout, “By the underbelly of Apophis, I get it already!”
If your purpose, in writing any particular story or portion thereof, is to convince your audience of something, it were better that you restrain from incessantly beating them over the head with your ideas, as that is about the least convincing thing you could do. Furthermore, regardless of your purpose, the aforementioned type of character repetition (and thus, theme repetition) breeds stilted and unbelievable characters who will utterly bore all as the reader has already met them a dozen or more times before! As with films, there are some books that are so profoundly bad they’re good precisely because they’re so humorously bad, but whoever heard of a book so boring that one simply must read it?