Metaphors construct they ways in which we experience and comprehend the world around us. More than just flowery description, metaphors are endemic to our cognition and structure how we interpret ideas and concepts. They therefore shape our perspective and influence our behaviour and responses. Metaphors "work" when they help us understand some aspect of what they describe. Metaphors help us determine what is real, what is important, and how we relate to the world around us. They help us interpret partially what we can't understand totally.
Metaphors allow us to organize and manage our experiences, and, by extension, reason about them. In fact, we need metaphors in order to rationally understand complex, abstract concepts. Generally, we use concrete metaphors to describe and structure less clearly delineated, nonphysical things.
[[Lakoff and Johnson - Metaphors We Live By|Lakoff, George, and Mark Johnson. Metaphors We Live By. University of Chicago Press, 2008.]]