Perhaps the best motivation for going to Mars is political. It is obvious that no single nation currently has either the will or the resources to do it alone, but a consortium of nations and space agencies could achieve it within 20 years.
“The conscious mind determines the actions, the unconscious mind determines the reactions; and the reactions are just as important as the actions.”
“Let's just say I decided that while my son is young I don't want to do projects that would take me away for months.”