Imagination, also called the faculty of imagining, is the creative ability to form images, ideas, and sensations in the mind without any immediate input of the senses (such as seeing or hearing). – Wikipedia.
Imagination is probably what most differentiates humans from other living beings. It is that wonderful ability to create new scenarios in our mind that do not really exist.
Our imagination combines desires, previous experiences, lived sensations, also our fears and hopes. The imagination transports us to new places that probably we would like them to exist.
We will only be aware of the importance of the imagination if we imagine that we did not have imagination. I firmly believe that if we did not have this incredible capacity, we would not be human, humanity would not exist.
I find it interesting that people have different levels of imagination and I think the best artists have a vivid imagination and a capacity to hold those visions and reproduce them. Us more mundane types tend to be more prosaic in our imaginings.