The reasonable man adapts himself to the world; the unreasonable one persists to adapt the world to himself. Therefore all progress depends on the unreasonable man.
If you have not even a little imagination, you are simply a brute. So you must not lower your ideal, neither are you to lose sight of practicality. We must avoid the two extremes.... You must try to combine in your life immense idealism with immense practicality.
When we decide to be happy we accept the responsibility to bring happiness to someone else. Some decide that happiness and glee are the same thing, they are not. When we choose happiness we accept the responsibility to lighten the load of someone else and to be a light on the path to another who may be walking in darkness.