The KISS principle

In the 14th century, William of Occam popularized the notion that "entities must not be multiplied beyond necessity" (entia non sunt multiplicanda praeter necessitatem) which has become known as Occam's razor.  Centuries later, Isaac Newton would recapitulate the idea: "We are to admit no more causes of natural things than such as are both true and sufficient to explain their appearances. Therefore, to the same natural effects we must, so far as possible, assign the same causes."  And of course, a couple centuries after that, Einstein famously quipped that we should strive to "Make everything as simple as possible, but not simpler."  Now, which one of those explanations/quotations do you prefer?  Well, if you are like most people, the Einsteinian explanation of Occam's razor stands out, which serves well to validate the idea that the simplest answer is usually the best.  Now, PsyBlog has a great little post summarizing some research on cognitive fluency, or, to simplify: simpler names and explanations are met with greater appreciation and less apprehension. Thus, further validation of Occam's appeal to Keep It Simple, Stupid (the aforementioned KISS principle).
Of course, all of this assumes that you want to be understood, or looked upon favorably, but, as every credit card company and government bureaucrat knows, "where there's confusion, there's money".  Thus, lengthy contracts and addenda let credit card companies get away with charging extra fees and exorbitant interest rates, and complicated legislation allows for lots of pork to be slipped in.  But, I guess the point of the research presented is, simplicity doesn't always equate with making money, rather, simplicity equates with being looked upon favorably... not something I would immediately think of when it comes to credit card companies and politicians.
(The figure is a schematic for all of the major biochemical pathways involved in metabolism.  It is a mainstay for many biochemistry textbooks, and, I imagine, for many students, myself included, it makes the brain want to immediately shut down)