In summary, the first and most primitive concept of the phenomenon referred to the limited sphere of those sensuously given realities through which Nature is evinced in perceiving. A metaphor, as we learned in our literature courses, is usually thought of as a poetic flourish. It is thought of as a device to emphasize a point and give a richer meaning to what we would like to communicate. It is, however, much more than that. It is found in everyday life, not just in language, but in thought and action.
Metaphors are the most striking evidence that humans think abstractly.
Metaphor uses concrete, sensory experience to convey an abstract idea. Metaphors are useful because they help us bridge ideas across domains and they are vivid because they so often are connected to our senses. Metaphors we live by. Some i nteresting metaphor links to Lakoff and Johnson can be reached here. Here is another take on metaphors.