This is the same despair created when we care too much about politics. We are too small to do anything big. Look at the greatest rulers in the past - all their accomplishments. This handful of world leaders and conquerors, all they've done, is hardly remembered or relevant. Genghis Khan may be the ancestor of millions of living people today, but he's still dead, and hardly any of his descendants know or care about their lineage.
Our sphere of influence is as big as we are, and only extends further so much as we can influence others. Unless we get something out of the extension of our influence, there's no reason to try. What could I want that I could get through influencing others? A family, a salary, friends, etc. What could I want from a galaxy?