At first glance, the myriad of interchangeable terms found in the English language appears to enhance its expressive power. On the contrary, the freedom that one has in choosing the precise words to express his/her ideas can sometimes hinder communication. Not only can one uncompress a sentence into its primary intended meaning, but one can also extract additional secondary information from the mere choice of words. This additional channel of information could be used for stealth communication between two parties; however, it is most often used for a slightly different purpose. By entering the world of metaphor and dabbling in the field of primary meaning invariance, one can encode a sentence with a hierarchy of secondary meanings. While also useful for surreptitious exchange of information, the plurality of meaning provides the author with a mechanism for saying things that they don't want to say directly.
But you might ask yourself: why encode nonlinear meaning into a message as opposed to keeping it straightworward? Isn't there a possibility that the receiving party will fail to receive the hierarchy of secondary meanings? Sure, if we aren't trying to hide anything from an intermediate party then this hierarchical injection of information does nothing but obfuscate the primary message. But some of us still do it on a daily basis. I'd like to know why. It's not like we're trying to be poetic here.