Imagination seems to have a most powerful impact on our lives, although we seldom stop to consider it.
Every once in a while, random changes may turn out to work out as improvements. Random improvements work well as an evolutionary mechanism on a geologic time scale. For humans, our brief span of life precludes us from using a similar strategy for improving our lives. In order to establish a habit of continuous improvement, we must practice imagining better ways of thinking, organizing or doing.
The better we become at using our imagination, the more we can create a fresh world. When we respond in an unusual way to a stimulus, we typically do so by engaging our imagination.
Forgiveness also requires imagination and courage. Retaliation is easy - folks choose it because they can't imagine a better way of resolving their grievance, and it may be perceived to satisfy a sense of fairness or justice. Forgiveness is hard - it requires imagining a world in which an agressor may go unpunished. Yet, the forgiver may imagine ways of influencing the forgiven such that the aggression ceases, amends are made, and harmony is achieved. That is very hard. Many despair of it being achievable, and can't imagine it possible.
Imagine more of us would make a habit of saying "I have a dream" more often...